L  Starland 

with   a 

Three -Inch  Telescope 


illiam  Tyler  Olcott 


>:*"•*:• 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Class 


BY  WILLIAM  TYLER  OLCOTT 


A  FIELD  BOOK- OF  THE  STARS 

IN  STARLAND  WITH  A  THREE-INCH  TELESCOPE 


In  Starland 
With  a  Three=Inch  Telescope 


A  Conveniently  Arranged  Guide  for  the  Use  of  the 
Amateur  Astronomer 

With  Forty   Diagrams   of  the    Constellations    and 
Eight  of  the  Moon 

By 

William  Tyler  Olcott 

Author  of  "A  Field  Book  of  the  Stars" 


OF   THE 

UNIVERSITY 

OF 


G.   P.   Putnam's  Sons 

New    York    and    London 

£be  Knickerbocker  press 

1909 


COPYRIGHT,  1909 

BY 

WILLIAM  TYLER  OLCOTT 


Ube  fmfcfcerbocfcer  press,  Hew 


OF   THE 

UNIVERSITY 

OF 


INTRODUCTION 

THE  sole  purpose  of  this  book  is  to  afford  a  convenient 
guide  for  the  amateur  astronomer  when  engaged  in 
telescopic  observation. 

Aside  from  a  study  of  the  moon's  surface,  the  observa- 
tion of  double  stars  is  sure  to  prove  the  most  attractive 
work  for  the  possessor  of  a  small  telescope.  The  brighter 
doubles  the  novice  will  have  no  difficulty  in  finding, 
but  those  below  the  third  magnitude  are  often  difficult 
to  locate  without  reference  to  a  diagram  of  the  constella- 
tion of  which  it  is  a  part — hence  the  author  has  seen  fit 
to  place  such  a  diagram  where  it  can  be  easily  consulted. 

It  is  presupposed  that  the  owner  of  the  telescope  is 
familiar  with  the  constellations.  It  then  should  be  an 
easy  matter,  with  the  assistance  of  the  accompanying 
diagrams,  to  find  the  double  stars  mentioned  in  the  text. 

The  constellations  are  grouped  under  the  seasons  for 
the  sake  of  convenience. 

Many  of  the  stars  have  faint  companions  of  the  ninth, 
tenth,  or  fainter  magnitudes.  These  doubles  are  inter- 
esting solely  to  those  who  desire  to  test  their  eyesight, 
or  the  powers  of  their  glass.  They  are  disappointing  as 
compared  with  the  beautiful  doubles  the  magnitude  of 
whose  components  are  more  nearly  on  a  par,  such  as 


211774 


iv  Introduction 

Castor,  (y)  Leonis,  (y)  Virginis.  The  author  has  there- 
fore arranged  the  doubles  to  be  noted,  so  that  those  most 
worthy  of  observation  come  first  in  the  column  assigned 
to  them. 

The  chapter  on  the  moon  is  arranged  according  to  the 
same  idea  as  the  matter  on  the  double  stars,  conciseness 
and  brevity  being  especially  aimed  at.  The  pleasures 
of  selenography  are  so  fascinating,  that  the  author  feels 
assured  that  the  student  will  add  to  the  brief  outline 
here  given  by  collateral  reading.  Only  the  principal 
objects  of  interest  are  mentioned  in  the  text  accompany- 
ing each  successive  view  of  the  moon.  The  observer 
will  note  a  wealth  of  detail  in  every  peep  he  takes  at  the 
moon  that  will  add  greatly  to  his  pleasure. 

In  a  word,  then,  the  raison  d'etre  of  the  book  is  con- 
venience of  arrangement.  The  author  has  found  by  ex- 
perience that  what  the  student  most  needs  when  he  is 
observing  with  the  telescope,  is  a  page  to  glance  at  that 
will  serve  as  a  guide  to  the  object  he  desires  to  view,  and 
which  affords  concise  data  relative  to  that  object.  The 
diagrams  therefore  direct  the  student's  vision,  and  the  sub- 
ject matter  affords  the  necessary  information  in  each  case. 

The  fact  that  there  are  so  few  telescopes  in  use,  com- 
paratively speaking,  in  a  great  measure  accounts  for  the 
little  interest  in  astronomy  taken  by  the  public.  If 
these  pages  serve  to  awaken  the  slightest  interest  in  the 
fascinating  study  of  the  heavens,  the  author  will  feel 
amply  repaid. 


THE  DIAGRAMS  OF  THE  CONSTELLATIONS 

THE  diagrams  represent  the  appearance  of  the  con- 
stellations in  the  season  in  which  they  are  placed, 
and  favorable  location  for  observation  was  chiefly  con- 
sidered in  thus  grouping  them.  The  student  can  vary 
the  arrangement  to  suit  his  convenience. 

As  the  winter  is  the  least  desirable  time  for  star-gazing, 
the  greater  number  of  constellations  have  been  purposely 
grouped  in  the  other  seasons. 

The  so-called  "  circumpolar  constellations"  are  of 
course  available  for  observation  at  any  time  of  the  year, 
and  the  student  can  choose  his  own  time  for  studying 
them. 

At  the  foot  of  each  diagram  of  a  constellation,  for 
ready  reference,  appears  the  name  and  page  number  of 
the  constellations  bounding  it. 

Only  the  constellations  visible  in  the  latitude  of  the 
New  England  and  Middle  States  have  been  included  in 
this  book. 

The  author  presupposes  that  the  telescope  to  be  used  in 
connection  with  this  book  is  not  equipped  with  circles, 
otherwise  recourse  should  be  had  to  some  such  book  as 
Webb's  Celestial  Objects  for  Common  Telescopes,  for  a  more 


vi    The  Diagrams  of  the  Constellations 

exact  location  of  the  objects  of  interest,  in  terms  of 
Right  Ascension  and  Declination. 

For  the  most  part  only  double  stars  with  a  primary 
of  the  sixth  magnitude  or  brighter  are  given,  as  it  is 
difficult  to  direct  the  telescope  at  a  star  of  lesser  magni- 
tude unless  its  position  is  accurately  known. 

In  searching  for  double  stars  many  faint  yet  beautiful 
pairs  and  triples  are  observed,  so  that  it  is  well  to  have 
such  a  book  as  Webb's,  in  order  that  these  objects 
can  be  identified. 

The  diagrams  include  over  three  hundred  double  stars, 
and  the  sight  of  these  and  the  many  fine  clusters  and 
nebulae  mentioned  should  afford  the  happy  possessor 
of  a  telescope  many  hours  of  keen  enjoyment. 

Considerable  discrepancy  will  be  noted  in  the  colors 
assigned  to  the  double  stars,  and  those  observed.  The 
coloring  in  many  cases  is  at  best  elusive,  and  atmo- 
spheric conditions  and  peculiarities  of  vision  play  an 
important  part  in  determining  it.  In  a  number  of 
cases  the  colors  are  very  pronounced  and  render  the 
object  of  surpassing  beauty,  as  for  instance  in  the  great 
favorite  (/?)  Cygni.  The  first  color  given  is  that  of  the 
primary  or  brightest  star,  the  second  color  given  is  that 
of  the  companion. 

The  position  angle  measures  the  inclination  to  the 
meridian  of  a  line  drawn  through  the  double  stars.  It 
shows  the  observer  where  to  look  for  the  companion  star, 
and  is  reckoned  from  o  degrees  to  360  degrees,  beginning 


The  Diagrams  of  the  Constellations   vii 

at  the  north  point,  and  proceeding  through  the  east, 
south,  and  west  to  the  north.  The  student  should  bear 
in  mind  in  this  connection  that  in  the  telescope  the  north 
and  south  points  are  reversed. 

The  decimals  are  omitted  from  the  distances  given 
between  the  doubles  (which  are  from  centre  to  centre,  and 
in  seconds  of  arc)  as  in  the  wider  doubles,  as  most  of 
those  referred  to  in  the  text  would  be  termed,  absolute 
accuracy  in  measurements,  for  purposes  of  observation 
purely,  is  non-essential. 

A  three-inch  glass  should  split  stars  that  are  distant 
from  each  other  2.3".  Of  course  this  question  of  splitting 
doubles  depends  in  a  great  measure  on  the  power  of  the 
eyepiece  used,  the  condition  of  the  atmosphere,  and  the 
quality,  of  the  eyesight  of  the  observer.  Serviss  recom- 
mends a  power  of  from  fifty  to  seventy  to  the  inch  of 
aperture.  The  author  has  succeeded  in  seeing  the  great 
majority  of  the  doubles  mentioned  in  the  text  with  a 
power  of  130. 

The  term  "light  year"  which  is  used  in  the  text  is  the 
usual  term  for  expressing  the  distance  from  the  earth  to 
the  stars.  A  light  year  is  the  unit  of  such  measurements, 
and  is  simply  the  distance  light  travels  in  a  year,  the 
speed  of  light  being  1 86 , ceo  miles  per  second.  Expressed 
in  figures  it  gives  5,785,344,000,000  as  the  distance 
in  miles  that  light  travels  in  one  year.  When  it  is 
added  that  (61)  Cygni,  the  nearest  star  to  the  earth 
m  the  northern  hemisphere,  is  nearly  six  light  years 


viii  The  Diagrams  of  the  Constellations 

away,  some  idea   of  the   profundity  of   space  is   made 

manifest. 

The  following  symbols  are  used  in  the  diagrams : 
O     The  outlined  circle  to  indicate  the  double  stars, 
-f-     The    cross    to    indicate    the     position     of    the 

nebulae. 

?;f    The  group  of  dots  to  show  the  location  of  the  star 

clusters. 

The  following  abbreviations  appear  in  the  text: 

A.,  Angle;  D.,  Distance;  H.,  Herschel;  Mg.,  Magnitude; 

M.,  Messier;  2,  Wm.  Struve;  O22,  Poulkova  Catalogue, 

Part  II;  P.,  Piazzi  Smyth;  OS,  Otto  Struve. 

In  the  compilation  of  this  book  I  desire  to  acknowledge 
my  indebtedness  to  Mr.  Garrett  P.  Serviss,  the  author 
of  The  Moon  and  Pleasures  of  the  Telescope.  These  books 
have  been  a  positive  inspiration  to  me,  and  the  student 
is  urged  to  include  them  in  his  collateral  reading. 

Mr.  Serviss,  than  whom  no  one  has  done  more  to  popu- 
larize the  charming  study  of  the  stars,  has  the  wonderful 
gift  of  imparting  knowledge  through  the  medium  of  a 
style  that  is  altogether  fascinating,  and  I  take  great 
pleasure  in  adding  my  mite  of  tribute  to  one  who  has 
afforded  me  through  his  numerous  writings  so  many 
hours  of  unalloyed  pleasure. 

In  preparing  the  list  of  objects  suitable  for  observation, 
I  derived  much  valuable  information  also  from  the  fol- 
lowing books: 


The  Diagrams  of  the  Constellations    ix 

Celestial  Objects  for  Common  Telescopes Webb 

Half  Hours  with  the  Telescope ..Proctor 

Hours  with  a  Three-inch  Telescope Noble 

Popular  Telescopic  Astronomy Fowler 

Astronomy  with  the  Naked  Eye Serviss 

The    Moon, . Proctor 

The  Friendly  Stars Mrs.  Martin 

Klein's  Star  Atlas. 

Ball's  Atlas  of  Astronomy. 

The  Nautical  Almanac. 


CONTENTS 

PAGE 

INTRODUCTION  .......        iii 

THE  DIAGRAMS  .          .          .          .  .         v 

The  Constellations  of  Spring. 

1.  CANCER  AND  CANIS  MINOR  ....         2 

2.  CORONA  BOREALIS       .....         4 

3.  CORVUS  AND  CRATER  .          ....         6 

4.  DRACO       .......          8 

5.  HERCULES          ......        10 

6.  LEO  .          .          .          .          .          .          .       12 

7.  LYRA         .          .          .          .          .          .          .14 

8.  VIRGO        .          .          .          .          .          .         .16 

The  Constellations  of  Summer. 

9.  BOOTES     .          .          .          .          .          .         .20 

10.  CANES  VENATICI  AND  COMA  BERENICES          .       22 

11.  LIBRA        .          .          .  .          .          .24 

12.  OPHIUCHUS  AND  SERPENS  26 


xii  Contents 


PACK 


13.  SAGITTA  AND  DELPHINUS     ....  28 

14.  SAGITTARIUS       ......  30 

15.  SCORPIO    .          .         .         .         ...          -32 

16.  URSA  MAJOR      ......  34 

17.  URSA  MINOR      ......  36 

The  Constellations  of  Autumn. 

18.  ANDROMEDA  AND  TRIANGULUM     ...  40 

19.  AQUARIUS           ......  42 

20.  AQUILA 44 

• 

21.  ARIES        .......  46 

22.  AURIGA     .......  48 

23.  CAPRICORNUS     ......  50 

24.  CASSIOPEIA         .         .         .         .         .  52 

25.  CEPHEUS             ......  54 

26.  CETUS       ........  56 

27.  CYGNUS     .......  58 

28.  PEGASUS  AND  EQUULEUS     ....  60 

29.  PERSEUS   .......  62 

30.  PISCES       .......  64 

31.  TAURUS 66 


Contents  xiii 

PAGE 

The  Constellations  of  Winter. 

32.  CANIS  MAJOR      ......  70 

33.  ERIDANUS           ......  72 

34.  GEMINI      .  .          .          .          .          -74 

35.  LEPUS        .....  -76 

36.  MONOCEROS        ......  78 

37.  ORION       .......  80 

The  Moon. 

PLATE      I. — SHOWING  THE   MOON  3.85  DAYS  OLD  90 

II. — SHOWING  THE  MOON  3.87  DAYS  OLD  92 

III. — SHOWING  THE  MOON  5.54  DAYS  OLD  94 

"      IV. — SHOWING  THE  MOON  5.74  DAYS  OLD  96 

V. — SHOWING  THE  MOON  7.75  DAYS  OLD  98 

VI. — SHOWING  THE  MOON  9.22  DAYS  OLD  100 

"     VII. — SHOWING  THE  MOON  11.78  DAYS  OLD  102 

'  VIII. — SHOWING     THE     MOON     14.40    DAYS 

OLD         ......  104 

LlST   OF  OCCULTATIONS   FROM  SEPT.    I,   1909,  TO 

JAN.  i,  1911         ......  106 


xiv  Contents 

PAGE 

THE  PLANETS  .          .          .          .          .          .          .in 

MERCURY  .         .         .         ...         .         .112 

VENUS  .......     113 

MARS     .  .          .          .          .          .          .          .113 

JUPITER  . 114 

PHENOMENA    OF    JUPITER'S    SATELLITES    DURING 

JULY  AND  AUGUST,  1909,  AND  THE  YEAR  1910     118 

EXPLANATORY  DIAGRAM  OF  THE  PHENOMENA  OF 

JUPITER'S  SATELLITES  .          .          .          .124 

SATURN 126 

URANUS  AND  NEPTUNE       .          .          .          .          .127 

PLANETARY  DATA  AND  DIAGRAM  SHOWING  THE 
POSITIONS  OF  THE  PLANETS  ON  THE  ECLIPTIC 
JANUARY  ist  FOR  TWELVE  YEARS  .  .  130 

THE  SUN 135 

INDEX 139 


THE  CONSTELLATIONS  OF  SPRING 


CANCER  AND  CANIS  MINOR 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

1 

4i-6* 

3°" 

308° 

Yellow,  blue. 

Good  contrast. 

Sl223 

6-6 

5" 

214° 

I/ 

6-7 

6" 

37° 

r 

S'0-Sr7 

O-"7 

Only     two      stars 

triple 

J5>£ 
6-7-7 

3-1" 

114° 

can      be       seen 
with    three-inch 

glass. 

21311 

7-7 

7" 

200° 

e 

5i-9 

61" 

66 

6-9 

4.8" 

136° 

Use  1  60  power. 

<£2 

6-6| 

5" 

212° 

64 

5i-9 

89" 

294° 

T     93    ' 

Lyncis 

6-8 

75" 

1  68° 

Gold,  azure. 

21245 
Hydrae 

6-7 

10" 

25° 

14 
Triple 

6-7-8 

II5;; 

75" 

154° 
65° 

In  Canis  Minor. 

Observe  the  "Bee  Hive"  with  a  low  power.  It  contains 
363  stars. 

Note  the  cluster  1712  (67  M.).  Herschel  observed  more  than 
200  stars  in  the  field  of  view  at  once. 

An  occultation  of  (7)  by  the  moon  frequently  occurs.  See 
List  of  Occultations,  page  — . 

(i)  was  discovered  to  be  double  by  Herschel,  1782.  Because 
of  the  much  anticipated  reappearance  of  Halley's  comet  in  1910, 
it  is  an  interesting  fact  that  this  comet  was  first  observed  in 
Cancer  in  1531. 

Observe  Castor,  that  gem  of  double  stars  in  Gemini. 

Procyon,  a  star  of  the  solar  type,  has  a  icth  magnitude  com- 
panion* green  in  color,  281"  distant.  It  is  12  light  years  dis- 
tant, ana  has  a  proper  motion  of  13  miles  per  second.  It  is  not 
definitely  known  whether  it  is  approaching  or  receding  from  the 
earth. 


CANCER  AND  CANIS  MINOR 


Of   THE 

(  UNIVERSITY  ) 


O2S93  Lyncii 


Castor 


Pollux 


OS  1323 


Procyon 


Gemini  Page  75 
Leo        Page  13 


CORONA  BOREALIS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

r 

4-5 

6.3" 

300° 

White,     blue,     or 

green. 

<r 

5-6 

4" 

206° 

X 

6-7 

95" 

1       57° 

21964 

7-7* 

i5" 

•    86° 

Note  (y),  a  naked  eye  double.  Distance,  6'.  angle,  165°.  Both 
deep  yellow.  They  both  have  a  faint  companion  too  difficult 
for  our  glass. 

(  +  )  marks  the  spot  where  a  famous  temporary  star  appeared 
in  1866  as  a  star  of  the  second  magnitude.  In  about  two  weeks 
it  declined  to  the  ninth,  its  present  magnitude.  It  was  the  first 
temporary  star  to  which  spectroscopic  analysis  was  applied. 
According  to  Webb  this  star  should  be  carefully  watched. 

The  star  (17)  is  too  close  a  double  for  our  glass.  It  is  a  binary 
with  a  short  period.  Webb  says,  "It  is  interesting  to  look  at  so 
wonderful  an  object  as  a  pair  of  suns  revolving  in  the  brief 
period  of  41.5  years." 

"  R  "  marks  one  of  the  most  remarkable  variable  stars  in  the 
heavens.  It  remains  sometimes  for  a  year  without  any  altera- 
tion in  light,  sometimes  falling  rapidly.  It  varies  from  a  magni- 
tude of  5.8  to  the  1 3th. 

Note  the  doubles  in  Serpens  and  Bootes  in  this  locality  as 
indicated  on  the  diagram. 


CORONA  BOREALIS 


O 


O  o 

x  S 1919  Bob'tis 


£021004        «T     *   ^m  Gemma 
t 


o 

X 

6  6 

0  ,° 

SERPENS 

Serpens  Page  27 
Bootes  Page  21 
Hercules  Page  11 


CORVUS  AND  CRATER 
CORVUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

5 

£1669 

3-8 
6*-6* 

24" 
5" 

211° 
299° 

Yellow,  purple. 
Fine    contrast. 

Note  (R)  recognized  as  a  variable  by  Karlinski  in  1867.  At 
maximum  it  reaches  the  seventh  magnitude,  declining  to  the 
eleventh  magnitude.  Period,  319  days. 

Observe  the  nebula  4361. 

CRATER 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

SI53° 

8-8 

7" 

314° 

H.  376 

Si-7 

8" 

211° 

This     star     is 
Hydra. 

m 

Just  west  of  (y)  is  a  double  (21473).  Magnitudes,  8-9.  Dis- 
tance, 30".  Angle,  10°. 

2 1'  north  15(1474).  Magnitudes,  7-8.  Distance,  71 ".  Angle, 
22°. 

A  line  drawn  from  (7),  to  (a),  prolonged  a  little  over  its  length, 
locates  a  remarkable  planetary  nebula  in  Hydra  (Herschel  27). 
"It  will  be  seen  like  a  pale  blue  disk,  like  the  ghost  of  Jupiter." 
It  is  just  south  of  the  fourth  magnitude  star  (/**)  Hydrae. 


CORVUS  AND  CRATER 


21530  o 


5 

O 

Hh.  378 

Hydrae 


4 

• 
£  Hydrae 


DRACO 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

V 

5-5 

62" 

312° 

A  grand  object. 

^ 

4-5 

3'" 

15° 

40,41 

5-6 

20" 

235° 

39 

5-8^-7 

3.6" 

360° 

Very  fine. 

Triple 

90" 

22° 

White,  blue,  red. 

J7 

6-6  f-6 

3-8* 

Il6°- 

Triple 

90" 

195° 

A  fine  sight. 

0 

4*-|* 

31" 

34i° 

Orange,  emerald. 

€ 

5-8 

3" 

5° 

Red,   blue. 

Good  contrast. 

I 

3~9 

255" 

5o° 

y 

2J-II 

125" 

116° 

21984 

6f-8i 

6.4" 

276° 

22604 

6$-Si 

27" 

184° 

22573 

6-8  J 

1  8" 

29° 

022123 
22348 

6f-7 

6-8 

-        68" 
25" 

i47: 
272° 

A  striking  object. 
Yellow,  blue. 

M 

5-5 

8.4* 

158° 

Both     white.      A 

beautiful     min- 

iature    of    Cas- 

tor. 

Note  Tuttle's  variable  nebula  4415. 

Look  south  of  (X)  a  degree  for  the  double  star  2^73.  Mag- 
nitudes, 6^-7^.  Distance,  69".  Angle,  147°. 

According  to  Flammarion  (o)  is  an  optical  double. 

It  is  an  interesting  fact  that  the  stars  which  are  not  visible 
to  the  eye  give  more  light  than  those  which  are  visible.  Approxi- 
mately speaking,  there  are  20  stars  of  the  ist  magnitude,  60  of 
the  2d,  1 80  of  the  3d,  and  so  on.  Multiplying  the  number 
of  stars  of  each  successive  magnitude  by  3  gives  the  number  of 
stars  of  the  next  fainter  magnitude. 


DRACO 


;  os  2 123 

.3 


6 

°2  1884 


Polaris 


°22323 


4 

O 
17 


22277 
Herculii 


S2234 


22004 

Hercules  Page  11 
Ursa  Major  Page  35 
Lyra  Page  15 


6 

o 

22573 


HERCULES 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

3-6 

4-7" 

118° 

Orange,  green. 

Good  contrast. 

I 

3-8 

if 

175° 

Green,  purple. 

7 

3*~~9 

38" 

242° 

White,  lilac. 

P 

4-5* 

3-7" 

3°9° 

Both    green, 
coloring  fine. 

95 

5-5* 

6" 

262° 

Apple  green, 

cherry  red. 

K 

5*—  7 

31" 

10° 

Yellow,  red. 

22IOI 

6-9 

4" 

57° 

22104 

6-8 

6" 

20° 

Pretty  double. 

A* 

4-9* 

3°'' 

241° 

IOO 

6-6 

182° 

A  beauty. 

83 

6-8* 

1  6" 

Distance  slowly 

increasing. 

22007 

6*-8 

32" 

328° 

22190 

6-8  } 

10* 

•      23° 

23 

6-9 

34" 

1  8° 

22063 

6-8 

1  6" 

194° 

22277 

6-8 

28" 

117° 

For  the  double  (m)  Hercules  see  Ophiuchus. 

The  cluster  4230  (M.iO,  a  superb  globular  cluster  discovered 
by  Halley  in  1714,  is  well  worth  observing.  Herschel  estimated 
that  it  contained  14,000  stars.  It  takes  a  four-inch  glass  to 
catch  the  twinkling  of  the  stars. 

According  to  Herschel  and  Argelander  the  solar  system  is 
moving  toward  (X). 

(5)  is  a  colored  variable  and  one  that  will  bear  watching, 
(a)  is  a  red  star,  one  of  the  type  with  banded  spectra.  A  circle 
described  with  (/*)  as  a  centre  and  a  radius  a  little  greater  than 
the  distance  from  (AC)  to  (X)  includes  the  result  of  five  standard 
computations  for  the  apex  of  the  solar  system, — the  point 
toward  which  the  sun  and  all  the  planets  are  speeding  at  the 
rate  of  14 \  miles  per  second. 


HERCULES 


032277 


Lyra  Page  15 

Draco  Page    9 

Corona  Borealis  Page    5 
Ophiuchus  Page  27 


II 


LEO 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

7 

2-4 

3-7" 

118° 

Finest    double    in 

northern       sky, 

according         to 

Struve. 

T 

5-7 

95" 

I70° 

Lemon,  light  blue; 

a     second    pair 

in  the  field  (83) 

54 

4i-7 

6" 

102° 

A  fine  sight. 

93 

5-8 

74" 

356° 

90 

6-7^—10 

3-5" 

209° 

Triple 

5Q" 

204° 

6 

6-9 

38" 

74° 

7 

6-8 

42" 

356° 

88 

7-9 

i5" 

320° 

Regulus  is  35  light  years  distant  from  the  earth.  According 
to  Huggins  it  is  receding  at  the  rate  of  twelve  to  seventeen  miles 
per  second.  It  has  a  proper  motion  of  eight  miles  per  second, 
and  is  a  star  of  the  Sirian  type.  There  is  a  distant  companion 
to  Regulus,  "seemingly  steeped  in  indigo,"  says  Miss  Clerke. 
Distance,  176".  Angle,  306°. 

The  variable  (R)  is  of  a  deep  red  color.  Its  period  is  3 1 2  days, 
and  it  fades  from  a  fifth  to  a  tenth  magnitude  star. 

Note    the    double    (35)    Sextantis.     6-7.     D.,    6".     A.,   240°. 

(j8)  has  a  distant  companion  of  the  eighth  magnitude. 

Note  the  nebula  1861-1863,  large  and  brilliant,  a  double 
nebula  in  powerful  telescopes. 

(7)  is  one  of  the  doubles  best  observed  when  it  is  not  quite 
dark  or  in  moonlight.  The  colors  of  the  stars  are  yellow  and 
green. 


12 


LEO 


6 

o 

35 

Sextantis 


+  +2038 


Cancer  Page    3 
Virgo    Page  17 


LYRA 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

€ 

ei  5-6 

3" 

15° 

A   double   double. 

e25~6 

2-3" 

133° 

The    four    stars 

are       doubtless 

physically    con- 

nected. 

r 

4-6 

44" 

150° 

Topaz,  green. 

ft 

4-7-8-1  i 

45" 

150° 

The      four      stars 

Multiple 

65" 

320° 

form  the    letter 

8f 

20° 

"Y." 

I 

44-8 

28" 

85° 

A     fine     field     in 

which    there    is 

another    double 

e 

44-94 

101" 

70° 

Yellow,  blue. 

Note  (/3)  Cygni,  one  of  the  most  beautiful  of  doubles. 

The  (  +  )  marks  the  location  of  the  famous  "ring  nebula" 
(57  M.).  In  a  three-inch  glass  it  has  a  dim,  misty  appearance, 
and  it  is  about  the  apparent  diameter  of  the  planet  Jupiter. 

Between  (e1)  and  (e2)  note  a  faint  star.  A  four-inch  glass 
reveals  two  other  stars  of  the  i2th  and  i3th  magnitudes  re- 
spectively, known  as  the  debillissima. 

Vega  has  a  tenth  magnitude  companion  48"  distant  to  the 
right  and  above.  No  trustworthy  parallax  has  been  found  for 
this  brilliant  star.  According  to  Huggins  it  is  approaching  the 
earth  at  the  rate  of  44  to  54  miles  per  second.  Its  proper 
motion  is  31  miles  per  second,  and  it  is  a  star  of  the  Sirian  type. 
The  field  about  (5)  is  glorious  for  low  powers.  The  sweeping 
between  Lyra  and  Cygnus  is  exceedingly  fine. 

(/3)  is  a  remarkable  variable.  Period,  12  days,  21  hrs. 
Maximum,  3.4  Mg.  Minimum,  4.3  Mg. 

In  the  great  Harvard  refractor  Vega  is  seen  with  no  less  than 
35  companions. 


LYRA 


Vega 


6 


0  Cygni 

Cygnus  Page  59 
Hercules  Page  11 
Aquila  Page  45 
Draco  Page  9 


VIRGO 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

7 

3-3 

5-8" 

150° 

Both    yellow, 
beautiful 

A 

ob- 

ject. 

21669 

6-6 

5-6" 

124° 

A  fine  pair. 

r 

4-8* 

79" 

290° 

21627 

6-6 

20" 

I96° 

2i682 

6^—9 

34" 

3°9° 

Yellow,  red. 

e 

4^-9-10 

7" 

345° 

Triple 

65" 

295° 

Many  nebulae  are  to  be  seen  in  the  bowl-shaped  region  formed 
by  the  stars  (/3),  (77),  (7),  (5),  (e),  which  is  called  "The  Field  of 
the  Nebulae. "  Use  about  40  power. 

(7)  is  a  variable  double.  Each  star  in  turn  declines  about 
half  a  magnitude,  and  recovers  within  a  few  days.  In  1756  the 
distance  between  the  components  was  6".  In  1836  the  two 
stars  were  so  close  together  that  they  could  not  be  split  with 
the  largest  telescopes.  Now  the  stars  are  5 . 8"  apart,  and  the 
distance  between  them  is  widening.  (7)  is  best  observed  in  the 
twilight  or  moonlight.  Its  period  of  revolution  is  180  years. 

Spica  is  of  the  Sirian  type  of  stars,  and  is  approaching  the 
earth  at  the  rate  of  from  9  to  14  miles  per  second. 

The  (  +  )  locates  the  nebula  3278.  Webb  says  it  resembles 
a  paper  kite,  and  that  it  is  beautifully  grouped  with  three 
stars.  There  are  two  nebulae  in  the  field. 

The  stars  (*),  (46),  (48),  (1),  (m),  (95),  («),  and  (X)  are  fre- 
quently occulted  by  the  moon. 


16 


VIRGO 


Denebola 


V 

21835 
Bootis 


\ 


•6 

3  Corvi 


Leo  Page  13 
Bootes  Page  21 
Libra  Page  25 
'Corvus  v 

and     [  Page   7 
Crater  » 


THE  CONSTELLATIONS  OF  SUMMER 


BOOTES 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

7T 

4-6 

6" 

99° 

Both  white. 

5 

3«i 

no" 

75° 

Yellow,  blue. 

V- 

4-7 

1  08" 

172° 

44 

5-6 

4.8" 

240° 

A  binary.    Period, 

261  years. 

39 

6-6 

3-6" 

45° 

Good    contrast   of 

colors. 

c 

4f-7i 

38" 

33° 

Yellow,  white. 

K 

5i-8 

12" 

238° 

White,    blue.      A 

beautiful        ob- 

ject. 

Sigig 

6-7 

25" 

10° 

Yellow,  white. 

Si85o 

6-7 

26" 

262° 

Yellow,  blue. 

2i835 

5  £-7 

6* 

1  86° 

* 

5-7 

3" 

200° 

Yellow,  purple. 

Fine  contrast. 

e 

2^-6 

2.8" 

326° 

Orange,  green. 

A  superb  sight. 

Arcturus  is  approaching  the  earth  at  the  rate  of  45  miles 
per  second.  "Its  excessive  remoteness  (Peters  gives  25  light 
years)  enables  us  to  recognize  in  it  perhaps  the  most  stupendous 
sun  within  our  imperfect  cognizance."  It  has  a  proper  motion 
of  372  miles  per  second,  is  a  star  of  the  solar  type,  and  has  a 
distant  companion  of  a  pale  lilac  color.  In  brilliance  it  is  equal 
to  5000  suns  like  ours. 

The  components  of  (f)  are  rapidly  narrowing.  In  a  few 
years  only  the  most  powerful  telescopes  can  split  it. 

(e)  was  called  "  Pulcherrima "  by  Smythe  on  account  of  its 
extreme  beauty.  A  power  of  160  is  recommended. 


Of   THE 

UNIVERSITY 

of 


BOOTES 


2  1919 


Ursa  Major          Page  35 

Corona  Borealis  Page    5 

Virgo  Page  17 

21 


CANES  VENATICI 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

Cor  Caroli 

3-6 

20* 

227° 

Both  yellow. 

2 

6-8 

II" 

260° 

Red,  blue. 

Fine  contrast. 

21615 

6-8 

26" 

88° 

Yellow,  ashy. 

i5 

5i-6 

2  go" 

297° 

7°  north-northwest  of  Cor  Caroli  is  "La  Superba, "  a  5th 
magnitude  star  of  brilliant  red  color.  It  is  one  of  the  seven  or 
eight  naked  eye  stars  of  the  4th  spectral  class,  and  is  noted  for 
the  brilliant  coloring  of  its  flashing  rays. 

Webb  describes  the  cluster  3636  as  a  brilliant  and  beautiful 
globular  congregation  of  not  less  than  1000  small  stars. 

South  of  "La  Superba"  is  a  fine  pair  of  7th  Mg.  stars.  The 
nebula  3572  is  the  "Spiral  or  Whirlpool  Nebula"  of  Lord  Rosse. 

COMA  BERENICES 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

24 

5-6 

20° 

270° 

Orange,  lilac. 

Fine  contrast. 

12 

5-8 

66" 

168° 

17 

5*-6 

145" 

250° 

White,  lilac. 

35 

5-9  % 

28" 

124° 

Lilac,  blue. 

2 

6-6  J 

3.6" 

24° 

Sl678 

6-7 

32;; 

211° 

32 

5-6 

194" 

48° 

Webb  says  of  this  constellation,  "A  gathering  of  stars  which 
obviously  require  distance  only  to  become  a  nebula  to  the  naked 
eye. " 


CANES  VENATICI  AND  COMA   BERENICES 
2 


;.  6 


2        A*** 
•       « 
17 

+  3572 


2 


7 


5 

•  La  Superba 


CANES    T"ENATICI 
4 


5 


5;  o 

•.5 

0o         OCorCaro11 


6  OS  1615 


•  5  5 


COMA    BEBENICES 


5 

2 

O        5 
32       •  5 

6 

°S  1678 


Ursa  Major   Page  35 
Bootes  Page  21 

Leo  Page  13 

23 


LIBRA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

I 

44-9 

57" 

110° 

Fine  contrast. 

212  P. 

6-7  i 

is" 

290° 

Sig62 

7-7 

12" 

l89° 

Pretty  object. 

H.4783 

6-9 

n" 

232° 

54  Hydrse 

6-7  * 

9" 

I29° 

According  to  Wilson  212  P.  resembles  61  Cygni.  Both  stars 
have  a  large  proper  motion  in  the  same  direction. 

(a)  has  a  fifth  magnitude  companion  visible  in  an  opera-glass. 
Magnitudes  3-6,  colors  yellow,  light  gray. 

(0)  is  the  only  naked  eye  star  green  in  color.  It  is  a  wide 
double  for  a  field-glass.  Colors,  emerald,  light  blue. 

A  line  drawn  from  (i)  to  (£)  Librae,  and.  prolonged  a  little 
beyond  its  length,  locates  the  cluster  4083  in  Serpens,  close  to 
the  fifth  magnitude  star  (5)  Serpentis. 

Stars  may  be  seen  in  the  daytime  with  even  a  small  telescope. 
It  is  said  that  a  telescope  of  i"  aperture  will  show  stars  of  the 
2d  magnitude.  For  those  who  care  to  try  the  experiment,  it 
is  suggested  that  a  planisphere  be  used  to  locate  some  such 
bright  landmark  as  Orion's  belt.  When  it  is  on  the  meridian 
there  should  be  little  difficulty  in  seeing  the  stars  even  in  broad 
daylight. 


24 


LIBRA 


H.  47S3 


212  P. 


A 

7Scorpii  O54Hydrae 


Scorpio  Page  33 

Virgo  Page  17 

Ophiuchus  and  Serpens  Page  27 


OPHIUCHUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

67 

4-8 

55" 

144° 

Yellow,  red. 

Fine  contrast. 

36 

5-7 

4-3" 

195° 

Yellow,  red. 

T 

5-6-9 

IOO 

127° 

Triple 

39 

6-7* 

ia* 

356° 

Yellow,  blue. 

Fine  contrast. 

S2i66 

6-7  * 

27" 

280° 

White/bluish. 

61 

53 

5*-6 
sf-7* 

a  i* 

4i" 

94o 
191° 

J9 

6-9 

22" 

93° 

70 

4*-  7 

5-5" 

148° 

Yellow,  red. 

p 

6-6 

4" 

i° 

Fine  close  pair. 

Yellow,  blue. 

Webb  says  the  neighborhood  of  the  new  star  1848  should  be 
watched. 

SERPENS 

(In    dotted   line.) 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

5 

3-4 

3-5" 

190° 

Both     white.       A 

fine  object. 

e 

4-4* 

2l" 

104° 

Both  yellow.     Lies 

in  rich  field. 

V 

5-9 

50" 

3'° 

Green,  lilac. 

ft 

3*~9 

30" 

265° 

Blue,  yellow. 

5 

5-10 

10* 

41° 

22342 

6-8 

26" 

120° 

Si93i 

6-7* 

13" 

I72° 

Observe  the  cluster  4083  close  to  (5) 
(70)  Ophiuchi  and  (v}  Serpentis  are  colored  variables. 
Note  (m)  Herculis.     Mg.,  6-8.     D.,  69".     A.,  230°. 

26 


OPHIUCHUS  AND  SERPENS 


's*«."    i-r- 

Scorpio 

Hercules  Page  11 
Scorpio  Page  33 
Sagittarius  Page  31 

27 


4083 

»voo  . 


SAGITTA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

€ 

6-8 

92" 

8l° 

J3 

6-7J 

340" 

13° 

e 

Triple 

7-9-8 

II" 

70" 

32?: 
227° 

f 

5-9 

8.6" 

3i2° 

Green,  blue. 

The  sweeping  in  this  region  is  magnificent. 

(a)  and  (/8)  are  both  wide  doubles. 

(15)  commands  a  fine  group.  A  few  minutes  north  of  it, 
is  a  beautiful  star,  sapphire  blue  in  color. 

(17)  lies  in  a  rich  region.  A  circle  around  it  of  30'  or  40'  radius 
will  include  several  very  pretty  little  8th  or  gth  magnitude 
pairs. 

Note  the  cluster  4520.  Webb  says,  "It  is  an  interesting 
specimen  of  the  process  of  nebular  resolution."  About  i° 
south  of  it  is  a  beautiful  low  power  field  containing  faint  pair 
and  triple  groups. 

DELPHINUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

7 

4-5 

II" 

273° 

Golden,  emerald. 

Fine  contrast. 

a 

4-9 

35" 

278° 

(6)  lies  in  a  beautiful  field. 
There  is  a  pretty  pair  in  the  field  with  (e). 
Just  S.  W.  of  (<p  is  a  triple  of  7^  magnitude  stars. 
Note  22628  Aquilae.     Mg.,  6-6.     D^,  60".     A.,  175°. 

28 


SAGITTA  AND  DELPHINUS 


SAGITTA 


*  I 


2*28 


Altaii 


Aquila  Page  45 
Cygnus  Page  59 
Pegasus  Page  61 


SAGITTARIUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

54 

6-7  i 

45" 

42° 

Yellow,  blue. 

A* 

3t-9i-io 

40" 

315° 

Triple 

45" 

114° 

22325 

6-9 

12" 

257° 

This    double    and 

the  one   follow- 

ing   are    in    So- 

bieski's  Shield. 

22306 

7-8 

12" 

219° 

Yellow,    blue.      A 

beautiful        ob- 

ject. 

There  are  many  fine  star  clusters  and  nebulae  in  this  region. 
Note  especially  the  clusters  M.  22,  M.  24,  M.  25.  They  are  all 
visible  to  the  naked  eye,  and  the  former  has  been  known  since 
1665.  Observe  the  so-called  "Trifid  Nebula"  4355  (M.  20),  also 
4403  (M.  17)  known  as  the  "Horse-shoe  Nebula,"  one  of  the 
nebula  that  can  be  observed  with  comparatively  low  optical 
power.  Muggins  has  shown  it  to  be  gaseous. 

M.  18  is  in  a  glorious  field.     "A  region  of  surpassing  splendor." 

About  i£°  south  of  (X)  is  a  fine  seventh  magnitude  triangle. 

It  is  seldom  that  more  than  2000  stars  are  visible  together 
to  the  naked  eye  up  to  the  6th  magnitude. 

Using  a  telescope  of  only  aj-inch  aperture  Argelander  regis- 
tered 324,189  stars  down  to  the  9^  magnitude. 

When  the  photographic  charting  of  the  sky  is  accomplished 
about  650,000  stars  will  be  identified  and  indexed. 

According  to  Newcomb,  the  total  number  of  the  stars  is  to  be 
counted  by  'hundreds  of  millions. 


3° 


SAGITTARIUS 


\ 


5    5 

•  O 

54 


o 

S2306 


+  M.17 
+  M.18 

'*£ 

M.24 


tf-M.25 


Capricornus  Page  51 
Scorpio  Page  33 

Aquila  Page  45 

31 


SCORPIO 


DOUBLE 
vSTAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

ft 

2-6 

13" 

30° 

White,  bluish. 

Fine  contrast. 

V 

4-7 

40" 

336° 

ff 

4-9 

20" 

272° 

White,  blue. 

g 

5-7 

7" 

65° 

White,  gray. 
Beautiful  field. 

p.  236 

6J-8 

4" 

23I° 

A  pretty  pair. 

p 

Ophiuchi 

6-6 

4" 

1° 

The  cluster  4264  in  Ophiuchus  was  discovered  by  Messier  in 
1764,  and  catalogued  as  a  nebula.  In  1784  Herschel  proved  it 
to  be  a  globular  cluster.  The  cluster  4268  was  discovered  by 
Herschel.  It  is  2'  in  diameter. 

4270  is  a  globular  cluster,  fairly  brilliant,  followed  by  a  faint 
nebula. 

(?)  Scorpii  is  said  to  be  the  most  beautiful  quadruple  group 
in  the  heavens. 

Herschel  thought  that  the  cluster  4173  (80  M.)  was  the  richest 
mass  of  stars  in  the  heavens.  On  the  eastern  side  of  this  cluster 
is  a  starless  spot,  a  "black  hole,"  similar  to  the  so-called  "coal 
sack"  in  Cygnus.  Webb  likens  it  to  a  comet. 

Antares  has  a  companion  of  the  7^  magnitude,  distant  3", 
angle  270°,  green  in  color.  Proctor  says  a  larger  glass  than  a 
four-inch  is  required  to  split  it. 

A  little  south  of  (£)  is  a  double,  21999.  Magnitudes,  7^-8, 
distance,  10",  angle,  103°. 

(/3)  may  be  an  optical  double. 


SCORPIO 


Ophiuchus  Page  27 
Libra  Page  25 

Sagittarius  Page  31 

33 


URSA  MAJOR 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

f 

2-4 

U* 

I48° 

Both  white.    Alcor 

in  the  same  field. 

23 

4-9 

23" 

272° 

Fine    contrast    of 

colors. 

0-2 

5-8 

4" 

263° 

57 

6-8 

5" 

4° 

2i4i5 

6-7 

1  6" 

167° 

21561 

6-8 

10" 

266° 

"  Prettily     group- 

ed." 

21495 

6-8 

35" 

38° 

Si  1520 

6  £-8 

i3" 

345° 

65 

6-8 

4" 

38° 

White,  blue. 

Note  the  two  fine  nebulas  separated  by  only  half  a  degree, 
1949  and  1950. 

2343  (M.  97)  is  a  large  planetary  nebula  called  "The  Owl 
Nebula."  South  of  the  so-called  "Spiral  Nebula"  in  Canes 
Venatici,  is  the  beautiful  and  easy  double  Cor  Caroli. 

(f)  is  probably  the  best  known  double  star  in  the  heavens, 
and  is  one  of  the  most  beautiful.  It  is  easy  to  find,  and  is  most 
effective  to  view  in  a  small  telescope.  It  was  discovered  by 
Riccioli. 

(7)  lies  in  a  fine  field. 

The  stars  (j3)  (7),  (5),  (e),  and  (17)  are  all  stars  of  the  Sirian 
type,  (a)  is  a  star  of  the  solar  type. 

(f)  and  (o)  are  spectroscopic  binaries.  The  former  was  the 
first  double  photographed  by  Bond. 

A  third  star  is  in  the  field  with  (65);  D.,  62".  A.,  113°. 


34 


URSA  MAJOR 


oS  1415 
+ 
1949 
1960 


Spiral 


Neb. 


21495 


OS  1520 


3 
• 


Q  Cor  Caroll 


°S  1561 


•* 

/* 


Canes  Venatici  Page  23 

Ursa  Minor  Page  37 

Draco  Page    9 

Bootes  Page  21 

35 


URSA  MINOR 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

2-9 

1  8" 

210° 

Yellowish-white 

and  blue. 

7T  ' 

6-7 

30" 

83° 

Both  yellow. 

40,    41 

Draconis 

5-6 

20" 

235° 

A  fine  double. 

OS  262 

7-8 

28" 

182° 

If  your  glass  is  a  good  one  and  the  atmospheric  conditions  are 
favorable,  you  should  have  no  trouble  in  seeing  the  companion 
to  Polaris.  Webb  states  that  it  is  easy  with  anything  much 
exceeding  2  inches.  If  it  is  difficult  to  see,  try  the  method  of 
inverted  vision,  or  gazing  at  a  distant  part  of  the  field.  This 
method  brings  into  use  a  more  sensitive  part  of  the  retina  and 
often  succeeds  admirably. 

Polaris  is  63  light  years  distant  (Peters  gives  35  years),  has  a 
proper  motion  of  2^  miles  per  second,  and  is  approaching  the 
earth  at  the  rate  of  16  miles  per  second.  It  is  a  star  of  the  Solar 
type.  At  the  distance  of  Polaris  our  sun  would  appear  with  an 
opera-glass  as  a  7 1  magnitude  star.  Polaris  is  one  of  the  spec- 
troscopic  binaries.  Its  period  is  3.97  days.  The  star  (40,  41) 
Draconis  is  given  here,  as  its  situation  renders  it  easy  to  observe 
when  the  telescope  is  directed  towards  Ursa  Minor. 


UPSA  MINOR 


o  40  Draconis 


OS  262 


K  Draconis 


Ursa  Major  Page  35 
Draco  Page    9 

Cepheus        Page  55 


37 


THE  CONSTELLATIONS  OF  AUTUMN 


39 


ANDROMEDA  AND  TRIANGULUM 

ANDROMEDA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

*""     7 

3-6 

10* 

62° 

Yellow,  blue. 

S79 
-  ic 

6-7 
4-8 

7" 
36" 

192° 
173° 

Very  beautiful. 
Yellow,  blue. 

<-.      56 

6-6 

181" 

301° 

59 

6-7 

1  6" 

34° 

Yellow,  blue. 

23 

7*-8* 

5" 

84° 

/* 

4-1  1 

49" 

110° 

The  "  -f  "  indicates  the^  location  of  the  great  nebula  which  can 
be  readily  seen  with  the  naked  eye,  and  the  only  one  which  was 
discovered  in  pre-telescopic  times.  Its  place  was  marked  on 
a  star  map  brought  from  Holland  believed  to  date  from  the 
loth  century.  It  is  known  as  "the  transcendently  beautiful 
queen  of  the  nebulae. "  It  is  a  disappointing  object  in  an 
ordinary  telescope. 

In  Aug.,  1885,  a  new  star  shone  up  in  the  very  midst  of  the 
great  nebula.  It  faded  to  invisibility  during  the  next  year. 
The  distance  of  the  nebula  from  the  earth  is  so  great  as  to 
render  abortive  all  attempts  to  measure  it  with  the  most  powerful 
instruments.  Its  dimensions  doubtless  are  inconceivably  enor- 
mous, and  beyond  comparison  with  those  of  the  Solar  System. 

(7)  is  one  of  the  most  beautiful  doubles  in  the  heavens.  It 
was  first  noticed  by  Mayer  in  1788.  The  contrast  of  colors 
is  very  fine. 

TRIANGULUM 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

6 

5-7 

3-8" 

77° 

Yellow,  blue.     An 
exquisite  pair. 

Note  the  nebula  352  discovered  by  Messier.     It  is  30'  in  extent. 
The  first  asteroid  to  be  discovered,  Ceres,  was  discovered  in 
Triangulum  in  1801. 

(7)  is  a  fine  naked  eye  triple. 

40 


ANDROMEDA  AND  TRIANGULUM 


Aries  Page  47 
Perseus  Page  63 
Pegasus  Page  61 
Cetus  Page  57 

41 


AQUARIUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

f 

4-4 

3* 

32I° 

Both  green.     Fine 

pair.          Period 

750  years. 

12 

6-6 

2.8" 

190° 

41 

6-8 

5" 

"5° 

Yellow,  blue. 

T 

6-9 

27" 

H5° 

White,  garnet. 

* 

4M 

5°" 

310° 

Yellow,  blue. 

Fine  contrast. 

69 

6-9 

28" 

"5° 

94 

13" 

345° 

Fine  contrast. 

22809 

3i" 

163° 

S2838 

6-8 

2l" 

185° 

53 

6-6 

7" 

3°4° 

For  the  double  107  Aquarii  see  Cetus. 

Look  for  the  nebula  4678,  a  beautiful  round  nebula  discovered 
by  Maraldi  in  1764.  A  fine  sight  in  a  three-inch  glass. 

Just  west  of  (t>)  is  a  fine  specimen  of  a  planetary  nebula,  4628. 
It  was  discovered  by  Herschel  in  1782.  Rosse  calls  it  the 
"  Saturn  nebula.  "  It  is  moving  toward  the  sun  at  the  rate  of  1 7 
miles  per  second.  Five  degrees  north  and  just  east  of  (/3)  is  2 
M.,  a  large  bright  nebula;  from  it  "streams  of  stars  branch  out, 
taking  the  direction  of  tangents.  "  1624  years  is  given  for  the 
period  of  (£).  About  4°  east  by  south  of  (5)  is  29,  a  fine  double. 


42 


AQUARIUS 


2  28090 


+  4678 


+  4028 


Fomalhant 


Cetus  Page  57 

Pisces  Page  65 

Pegasus         Page  61 
Capricornus  Page  51 


43 


OF   THE 

UNIVERSITY 


AQUILA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

57 

5-6 

36" 

-I70° 

Yellow,  green. 

Fine  double. 

15 

6-6 

35" 

206° 

White,  lilac. 

6-7 

i3" 

121° 

White,  bluish. 

28 

6-8 

60" 

175° 

1  1 

Si-9 

1  8* 

242° 

Optical  double. 

22644 

6-7 

3.6" 

208° 

Primary       bluish, 

white. 

22654 

6-8 

12" 

234° 

22446 

6-8 

10* 

154° 

22628 

6-8 

4" 

349° 

Yellow,  purple. 

Altair  is  16  light  years  distant,  has  a  proper  motion  of  9 
•miles  per  second,  and  is  approaching  the  earth  at  the  rate  of 
27  miles  per  second.  It  is  a  star  of  the  solar  type,  and  has  a 
tenth  magnitude  companion.  Distance,  15 2".  Angle,  322°. 

R.  is  a  variable  of  a  deep  red  color.  At  maximum  its  magni- 
tude is  6J.  At  minimum,  n.  Its  period  is  351  days. 

(?;)  is  a  variable  with  maximum  3 £,  minimum  4.7  magnitude. 
Its  period  is  7  days,  4  hours. 

Struve  gave  white  as  the  color  of  both  of  the  stars  in  (57). 

Note  the  cluster  4440.  A  beautiful  object  consisting  of  stars 
of  the  ninth  to  the  twelfth  magnitudes. 


44 


AQUILA 


0Serpentis 


22644 


22854 


Cygnus  Page  59 
Lyra  Page  15 

Ophiuchus  Page  27 
Capricornus  Page  51 
Delphinus  Page  29 

45 


ARIES 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

7 

4-4  i 

8" 

359° 

White,  yellow. 
Disagreement  as 

to  colors. 

X 

5-8 

37" 

45° 

White,  lilac. 

14 

54-9-7 

93" 

36° 

White,  blue,   lilac. 

Triple 

1  06" 

278° 

3° 

6-7 

38" 

273° 

Both     white.       A 

beautiful      dou- 

ble. 

33 

6-9 

28" 

0° 

Topaz,  sapphire. 

7T 

5-8-1  i 

3-24" 

122° 

Triple 

25" 

110° 

i 

6-7 

2.6" 

I70° 

(a)  is  40  light  years  distant,  and  has  a  proper  motion  of  eight 
miles  per  second.  It  is  a  star  of  the  solar  type. 

(7)  was  the  first  double  discovered.  It  was  discovered  by 
Hooke  in  1664,  when  he  was  following  a  comet. 


ARIES 


5 
•     6 


Taurus         Page  67 
Pisces  Page  65 

Cetus  Page  57 

Andromeda  Page  41 

47 


AURIGA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

26l6 

5-9 

6" 

350° 

Greenish,  white. 

26 

5-8-1  i 

12" 

268° 

Yellow,  blue. 

Triple 

26" 

H3° 

14 

5-7^-1! 

I4" 

224° 

Yellow,  blue. 

Triple 

12" 

342° 

X 

5-9 

I2l" 

13° 

4i 

5-6 

8" 

354° 

White,  violet. 

2872 

6-7 

II* 

217° 

Yellow,  lilac. 

2645 

6-8 

12" 

27° 

White,  ash. 

S68i 

6J-9 

23" 

181° 

S6g8 

6-7i 

3i" 

346° 

Yellow,  bluish. 

Beautiful. 

S764 

6-7 

25" 

13° 

56 

5i-8 

48" 

21° 

S533 

Hrl 

20* 

60° 

In  Perseus. 

2552 

6-6 

0* 

H4° 

In  Perseus. 

Smythe  describes  the  cluster  1119  as  "an  oblique  cross,  with 
a  pair  of  large  stars  in  each  arm,  and  a  conspicuous  one  in  the 
centre,  the  whole  followed  by  a  bright  star  of  the  seventh 
magnitude.  "  There  are  several  wide  doubles  scattered  through 
it  and  the  whole  region  is  very  beautiful.  Of  the  cluster  1295 
Webb  says,  "Even  in  small  instruments  it  is  extremely  beauti- 
ful. One  of  the  finest  of  its  class."  Capella  is  probably  30 
light  years  distant.  Peters  gives  70  light  years,  Struve  n.  It 
has  a  proper  motion  of  n  miles  per  second,  and  is  receding 
from  the  earth  at  the  rate  of  17  or  23  miles  per  second.  It  is 
a  model  star  of  the  solar  type. 

The  light  of  (f)  is  singularly  intense  for  its  magnitude. 


AURIGA 


1451 


Nath    SMS 


Perseus  Page  63 
Taurus  Page  67 
Gemini  Page  75 


o 
S533 


49 


CAPRICORNUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

4-8* 

44" 

7-4* 

220° 
I50° 

A  naked  eye  dou- 
ble,    and     tele- 

scopic      double 

double. 

Both  yellow. 

ft 

3-6 

205" 

267° 

Gold,  blue. 

o 

6-7 

22" 

240° 

WThite,  bluish. 

A  pretty  pair. 

ff 

6-9 

54" 

177° 

Orange,  blue. 

IT 

5-9 

3-4" 

145° 

P 

5-8 

3-8" 

177° 

Yellow,  purple. 

Fine  contrast. 

Note  the  star  cluster  30  M.  It  lies  a  little  north  of  (41),  a 
fifth  magnitude  star.  Webb  describes  it  as  "moderately 
bright,  beautifully  contrasted  with  an  eighth  magnitude  star 
beside  it."  Use  a  power  of  about  70. 

00,  (P).  and  (o)  form  a  pretty  little  triangle  of  fifth  magnitude 
stars. 

In  a  good  glass  five  stars  should  be  seen  in  the  field  with  (a). 


CAPRICORNUS 


41 


Aquarius      Page  43 
Aquila  Page  45 

Sagittarius  Page  31 


CASSIOPEIA 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

•n 

4-7* 

5" 

200° 

White,  purple. 

<r 

5-7 

3" 

324° 

Green,  blue. 

Coloring 

intense. 

* 

4*-8* 

30" 

101° 

c 

4-8 

7" 

112° 

a 

2-9 

62" 

280° 

Si63 

6-8 

35" 

33° 

Gold,  blue. 

Remarkable 

colors. 

S3°53 

6-7 

IS* 

7o° 

Yellow,  blue. 

Sigi 

6-8f 

5" 

190° 

OSS26 

6-6  1 

63" 

199° 

Orange,  green. 

(7)  and  (K)  both  lie  in  very  rich  fields.  Half-way  between 
them,  note  a  fine  cluster  somewhat  in  the  shape  of  the  letter 
"  W."  Between  (TT)  and  (o)  is  a  glorious  field. 

(17)  was  discovered  by  Herschel  in  1779.  It  is  a  binary  with 
a  period,  according  to  Doberck,  of  222^  years.  Duner  gives 
176  years.  Struve  gives  the  distance  as  22  light  years.  (17) 
and  70  Ophiuchi  are  similar  systems,  both  have  about  the  same 
proper  motions  and  parallax,  and  identical  spectra  of  the  solar 
type. 

(a)  is  47  light  years  distant,  and  has  a  proper  motion  of  two 
miles  per  second.  It  is  a  star  of  the  solar  type. 

(/3)  is  20  light  years  distant,  with  a  proper  motion  of  ten  miles 
per  second. 

(7)  is  a  gaseous  star,  and  belongs  to  the  5th  spectral  class. 

The  (  +  )  marks  the  position  of  Tycho's  star,  the  famous  vari- 
able of  1572. 

Note  especially  the  clusters  392  and  256.  The  latter  con- 
tains a  double,  magnitudes  8-9. 


CASSIOPEIA 


Cepheus  Page  55 
Andromeda  Page  41 
Perseus  Page  63 
Pegasus  Page  61 


53 


CEPHEUS 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

ft 

3-8 

// 

2500 

White,  blue. 

8 

4j—  7 

41" 

I92° 

Yellow,  blue. 

e 

4  4-6* 

6.8" 

282° 

Yellow,  blue. 

K 

4-8 

i~n 

124° 

White,  blue. 

228i6 

6-8-8 

12" 

120° 

Triple 

20" 

339° 

22893 

5i~7i 

28" 

348° 

Yellow,  white. 

22840 

6-7 

20" 

194° 

Greenish       white, 

bluish  white. 

A  splendid  pair. 

22873 

6-7 

13" 

77° 

22883 

6-8 

15" 

254° 

White,  blue. 

Note  (A*),  the  so-called  "garnet  star,"  the  reddest  star  in  the 
northern  hemisphere. 

Many  small  meteor  showers  radiate  from  Cepheus  during 
the  middle  and  latter  part  of  June. 

The  double  23053  Cassiopeiae  is  given  here,  as  it  is  conveniently 
located  to  observe  while  the  student  is  exploring  Cepheus. 
Magnitudes,  6-7.  Distance,  15".  Angle,  70°.  Yellow,  blue. 

(5)  is  a  beautiful  double  and  has  been  likened  to  the  celebrated 
08)  Cygni. 


54 


CEPHEUS 


S2873 


O 
Polaris 


Cassiopeiae 


Cassiopeia  Page  53 
Cygnus  Page  59 
Draco  Page  9 

Ursa  Minor  Page  37 


55 


CETUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

26 

6-9 

I  6" 

252° 

Topaz,  lilac. 

-n 

sH>* 

225" 

3050 

r 

3-9 

185" 

40° 

7 

3-7 

3" 

288° 

Yellow,  blue.      A 

beautiful      dou- 

ble. 

37 

5-7 

So" 

33i° 

66 

6-8 

IS* 

228° 

Yellow,  blue. 

239 

6-8  J 

20" 

45° 

Yellow,  bluish. 

16 

6-8  J 

65" 

289° 

2150 

7-8 

36" 

195° 

A  fine  double. 

2274 

7-7* 

13* 

218° 

84 

6-9 

4* 

334° 

SI6 
107 

st? 

81" 
6" 

162° 
138° 

Coloring  fine. 

Aquarii 

a 

2J-XO 

258° 

A     wide     double. 

Note    a    blue     5^ 

Me.     star    in    the 

field. 

(x)  has  a  seventh  magnitude  companion  distant  3'. 

Note  the  nebula  138  discovered  by  Caroline  Herschel  in  1783. 
It  is  described  as  being  long,  narrow,  and  bright. 

The  famous  variable  Mira  is  in  Cetus.  It  was  first  observed 
as  a  variable  by  Fafcricius  in  1596.  It  varies  from  the  second 
to  the  ninth  magnitude.  Its  period  averages  331  days.  Mira 
is  a  red  star  with  banded  spectra. 


CETUS 


o 

107 
Aquarii 


138 


Pisces  Page  65 
Taurus  Page  67 
Aquarius  Page  43 
Aries  Page  47 
Eridanus  Page  73 

57 


CYGNUS 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

ft 

3-7 

34" 

55° 

Yellow,  blue. 

Very  fine. 

52 

4-9 

6" 

60° 

Yellow,  blue. 

Good  contrast. 

17 

5-8 

26* 

73° 

Red,  blue. 

02 

4-7* 

4-5* 

10  7" 
358" 

I74o 
324° 

Orange,  blue. 
Good  contrast. 
A    double    dou- 

ble. 

* 

$H* 

3* 

184° 

White,  lilac. 

61 

6-6 

a  i* 

122° 

6   light  years  dis- 

tant.       Nearest 

to  earth  in  the 

northern    hemi- 

sphere. 

59 

5-9 

20" 

352° 

A* 

5-6-7  $-1  a 

2-4" 

121° 

A  quadruple  star. 

208" 

56° 

35" 

264° 

16 

sHt 

37" 

I360 

26 

$-»i 

4i" 

146° 

Yellow,  blue. 

48 

6-6 

178" 

174° 

S2486 

6-6} 

10" 

224° 

22578 

6*-7* 

15" 

I27° 

X1 

5-9 

26" 

73° 

In  fine  field. 

3 

6-6 

54" 

5° 

Observe  with  a  low  power  the  wonderful  star  stream  about  (7). 

"  +  "  locates  the  celebrated  "Dumb-bell "  nebula  in  Vulpecula 
(M.  27).  Use  a  low  power. 

(a)  or  Deneb  is  approaching  the  earth  at  the  rate  of  36  miles 
per  second.  According  to  Newcomb  it  will  eventually  become 
so  near  a  neighbor  as  to  outshine  during  several  thousand  years 
every  visible  star. 

Between  (a)  and  (e)  is  the  dark  rift  in  the  Milky  Way  called 
the  "  coal  sack. " 

3 30  separate  photographs  were  taken  of  (61)  in  1886-7.  These 
furnished  material  for  30,000  measurements. 

58 


CYGNUS 


K  Pegasi 


Lyra  Page  15 
Pegasus  Page  61 
Aquila  Page  45 
Cepheus  Page  55 

59 


PEGASUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

6 

2^-8 

138" 

324° 

Yellow,  violet. 

Coloring  fine. 

I 

4i-8J 

37" 

3IO° 

3 

6-7* 

39" 

349° 

22841 

6  £-8 

22" 

in0 

S2848 

7-7* 

10" 

54° 

There  is  a  pretty  pair  in  the  field  with  (3);  Mg.,  8-8,  D.,  7", 

A.,  349°- 

The  cluster  15  M.  was    discovered  by  Maraldi  in  1745. 

03)  is  a  variable  and  shows  a  beautiful  spectrum,  with  the 
dark  bands  of  Class  1 1 1 . 

Within  the  square,  Argelander  counted  30  naked  eye  stars. 
Note  22894  Lacertae,  Mg.,  6-8,  D.,  15",  A.,  193°;  also  8  Lacertae, 
a  beautiful  quadruple  star. 

(ir1)  and  (r2)  form  a  grand  pair.  North  of  them  2°  is  a  fine 
double,  22905;  Mg.,  8£-8J,  D.,  3",  A.,  283°. 

(e)  exhibits  a  phenomenon  noticed  by  Herschel,  viz. :  the 
pendulum-like  oscillation  of  a  small  star  in  the  same  vertical 
with  a  large  one,  when  the  telescope  is  swung  from  side  to  side. 

(7)  and  (17)  have  faint  companions  of  the  nth  Mg.,  D.  162" 
and  90"  respectively. 

EQUULEUS 


DOUBLE 

MAGNI- 

DISTANCE 

ANGLE 

REMARKS 

STAR 

TUDES 

6 

6-7 

II* 

75° 

White,  blue. 

X 

6-6 

2.6" 

225° 

A  fine  pair. 

7 

4i-6 

366" 

Yellow,  white. 

ft 

5-ioi 

67" 

309° 

8  has  a  companion  of  the  tenth  magnitude,  D.,  27",  A.,  38°,  and 
is  remarkable  for  the  fact  (I  quote  from  Mrs.  Martin's  Friendly 
Stars')  "that  it  is  supposed  to  have  a  period  of  only  5  years, 
the  shortest  yet  discovered  for  a  visual  binary. " 

60 


PEGASUS  AND   EQUULEUS 


Andromeda  Page  41 
Aquarius  Page  43 
Pisces  Page  65 

6l 


PERSEUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

•n 

4-8 

28* 

300° 

White,  blue. 

Several        faint 

stars  near  it. 

€ 

3-8 

9" 

9° 

r 

3-9 

13* 

207° 

A  quintuple  star. 

57 

5-6 

114* 

I98° 

Yellowish,  lilac. 

2552 

6-6  J 

9" 

H4° 

Both  white. 

2331 

5-7 

12" 

85° 

S533 

6-7  J 

19" 

60° 

2369 

6i-8 

3-5" 

28° 

Yellow,  blue. 

0 

4*-9i 

20" 

237° 

(a)  is  44  light  years  distant,  and  has  a  proper  motion  of  one 
mile  per  second.  It  is  approaching  the  earth  at  the  rate  of  7 
miles  per  second. 

Algol  is  approaching  the  earth  at  the  rate  of  two  miles  per 
second.  It  is  a  star  of  the  Sirian  type.  The  variability  of 
Algol  was  doubtless  discovered  in  very  ancient  times.  Its 
period  is  2  days,  20  hrs.,  48  m.  During  2  hrs.,  14  m.,  Algol 
appears  of  the  second  magnitude,  the  remaining  6f  hrs.  are 
occupied  by  a  gradual  decline  of  the  star  to  the  fourth  magnitude, 
and  its  equally  gradual  return  to  the  second  magnitude.  The 
variability  is  caused  by  the  periodic  eclipse  of  Algol  by  a  dark 
companion,  whose  distance  from  Algol  is  three  million  miles. 

The  clusters  512'  and  521  are  considered  the  finest  in  the 
heavens. 

The  cluster  584  has  a  diameter  of  15'.  Over  100  stars  can  be 
counted  in  it.  Very  fine  low  power  field. 


62 


PERSEUS 


•3  512 


Andromedae 


#584 


Algol 


•3717 


02533 


Capella 


Andromeda  Page  41 
Auriga  Page  49 
Cassiopeia  Page  £3 

63 


PISCES 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

3-4 

3' 

320° 

Green,    blue.        A 

fine   double. 

The    movement 

of  the  compan- 

ion is  very  slow. 

J 

5-6 
$1-5* 

24;; 

64° 
1  60° 

A  beautiful  sight. 
No   change   noted 

in  130  years. 

55 

5-8 

6" 

•192° 

Yellow,  blue. 

Two      beautiful 

stars. 

65 

6-6 

4.5" 

118° 

77 

6-7 

33" 

82° 

White,  blue.      No 

change  noted. 

35 

6-7  * 

ii* 

150° 

White,  purple. 

5-9 

27" 

82° 

Pretty  pair. 

38 

71-8 

4.5" 

240° 

Yellow,  white. 

42 

6-1  1 

29" 

3380 

Topaz,  emerald. 

(p)  and  (94),  both  fifth  magnitude  stars,  form  a  splendid  pair. 

(K)  is  in  a  fine  field. 

Note  the  nebula  307.     There  are  four  faint  stars  near  it. 

(7)  Arietis  is  a  fine  double  in  this  part  of  the  heavens.  See 
Aries. 

(£)  is  a  spectroscopic  binary. 

Viewed  with  the  Lick  refractor  of  36  inches,  any  given  star 
is  32,400  times  brighter  than  when  shown  by  a  2-inch  telescope. 

(?)  is  frequently  occulted  by  the  moon. 


64 


PISCES 


5/     ?7Andromedae 

V  o. 

Xf/ 


JT 

0 

42 

3 

%  7Pegasi 

X 

Neb.     5         4             4 

307         A          •             A 

-—2 

^035 

OU(^^Q  «0  .  

P-                      .6. 
o 
77 

51 

Aries 
Cetus 
Pegasus 
Andromeda 

Page  47 
Page  57 
Page  61 
Page  41 

65 


TAURUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

2430 

6-9-9! 

26" 

55° 

Triple 
30 

5-9 

39^ 

9" 

302° 
58° 

Emerald,  purple. 

6-8 

56" 

242° 

Red,  blue. 

2674 
2716 

6-9 
6-7 

10" 

5" 

I47o 
200° 

A  beautiful  pair. 

r 

5-7 

62" 

212° 

White,  blue. 

2548 

6-8 

14" 

35° 

2495 

6^-9 

4" 

216° 

X 

6-8 

19" 

25° 

in 

5^—8 

75" 

271° 

273o 

6|~7 

10" 

142° 

62 

6-8 

28" 

289° 

Fine  field. 

88 

4-7* 

69" 

299° 

o2 

5-7-8 

39" 

3°4° 

In  Orion. 

54" 

88° 

Beautiful. 

(01)  and  (02)  are  a  naked  eye  pair,  (cr)  has  a  naked  eye 
companion. 

Aldebaran  has  a  tenth  magnitude  companion,  D.,  114*,  A., 
35°,  and  is  a  standard  first  magnitude  star.  It  is  28  light  years 
distant,  has  a  proper  motion  of  four  miles  per  second,  and  is 
receding  from  the  earth  at  the  rate  of  30  miles  per  second.  It 
has  a  spectrum  of  the  solar  type. 

Alcyone  (17),  the  lucida  of  the  Pleiades,  is  a  quadruple  star  and 
a  very  beautiful  object. 

The  Pleiades  are  probably  250  light  years  distant.  They 
have  a  common  proper  motion,  and  a  spectrum  of  the  Sirian 
type.  A  photographic  plate  of  them  shows  over  2000  stars. 

The  (  +  )  locates  the  celebrated  "Crab  Nebula,"  the  first 
nebula  discovered  by  Messier.  Note  the  field  about  (f). 

66 


TAURUS 


2 

• 
0 

6 
2716 


4 

.0 


0 
o 

2548 

5 
O 

I 


The 

Pleiadt 


1157 


o 

2  674 


o 
2730 


AMebarau 


o 
111 


6 
o 

2495 


5 

O 
02Orlonis 


24300 


Perseus  Page  63 
Orion  Page  81 
Auriga  Page  49 
Gemini  Page  75 
Cetus  Page  57 

67 


THE  CONSTELLATIONS  OF  WINTER 


CANIS  MAJOR 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

V- 

5-8 

2.8" 

343° 

White,  blue. 

I/' 

5*-8 

17" 

262° 

H-3945 

7-8 

28" 

67° 

A  fine  pair. 

€ 

2-9 

f 

1  60° 

The  cluster  1454  is  a  superb  group  visible  to  the  naked  eye. 
Look  for  a"  red  star  in  its  centre. 

Sirius  is  a  double,  but  too  close  for  our  telescope.  It  is  eight 
light  years  distant,  and  has  a  proper  motion  of  nine  miles 
per  second.  According  to  Huggins  it  is  receding  from  the 
earth  at  the  rate  of  eighteen  to  twenty- two  miles  per  second. 
Vogel  raises  this  to  forty-six  miles.  Sirius  is  the  brightest 
representative  of  the  great  spectroscopic  type  i,  which  includes 
more  than  half  of  all  the  stars  yet  studied.  This  brilliant  sun 
is  supposed  to  be  surrounded  by  an  enormous  atmosphere  of 
hydrogen.  It  is  63  times  as  bright  as  our  sun. 

Our  sun  would  appear  as  a  third  magnitude  star  if  as  distant 
from  the  earth  as  is  Sirius. 

Note  the  nebula  1511  and  the  curving  row  of  faint  stars  near 
it. 


70 


CANIS  MAJOR 


Monoceros  Page  79 
Lepus  Page  77 
Orion  Page  81 


71 


ERIDANUS 


DOUBLE 

STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

32 

5-7 

6.7" 

348° 

Topaz,  bluish. 

Fine  contrast. 

Discovered     by 

Herschel,  1781. 

62 

6-8 

63" 

73° 

S422 

6-8 

6" 

232° 

Gold,  blue. 

39 

6-9 

6-4" 

150° 

55 

7-7 

10" 

3i8° 

Yellow,  white. 

2570 

7-8 

12" 

258° 

S436 

7-8 

3°" 

232° 

7 

2^—10 

51* 

238° 

02 

4-10 

82" 

105° 

Discovered  by 

Herschel,  1783. 

Note  the  planetary  nebula  826.     Lalande  described  it  as  the 
most  extraordinary  object  of  the  kind  he  had  ever  seen. 


72 


UNIVERSITY 

or 
lUFQRHi! 


ERIDANUS 


Orion  Page  81 
LepusPage  77 


73 


GEMINI 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

2~3 

6" 

226° 

Both    yellow.      A 

beautiful        ob- 

ject. 

r 

3-7 

90" 

355° 

Yellow,  blue. 

15 

6-8 

33" 

205° 

White,  blue. 

38 

6-8 

6-5" 

162° 

Yellow,  blue. 

Fine  contrast. 

d 

3-8 

7" 

197° 

Yellow,  purple. 

e 

3-9 

no" 

94° 

V 

4-8 

1  1  2" 

329° 

20 

6-7 

20" 

209° 

X 

3i~10 

10* 

3i° 

Greenish,  blue. 

K 

4-10 

6" 

231° 

Very  beautiful. 

(TT)  and  (A*)  both  have  eleventh  magnitude  companions 
distant  22"  and  73"  respectively. 

(7)  has  a  remarkable  array  of  stars  near  it. 

Castor  is  considered  the  finest  specimen  of  a  binary  in  the 
northern  hemisphere.  The  stars  make  a  complete  revolution 
in  about  1000  years.  Castor  was  the  first  star  shown  to  be 
certainly  of  a  binary  character.  It  has  a  spectrum  of  the 
Sirian  type. 

The  cluster  1360  is  one  of  the  finest  clusters  in  the  heavens. 
"A  marvellously  striking  object.  No  one  can  see  it  for  the  first 
time  without  an  exclamation." 

Pollux  is  48  light  years  distant,  has  a  proper  motion  of  27 
miles  per  second,  and  is  approaching  the  earth  at  the  rate  of 
33  miles  per  second.  It  is  a  coarse  but  fine  triple  star. 

The  region  about  (17)  is  very  rich. 


74 


GEMINI 


Pollux 


Orion  Page  81 
Monoceros  Page  79 
Taurus  Page  67 
Auriga  Page  49 


75 


LEPUS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

a 

3-10 

35* 

I560 

7 

4-8 

94" 

349° 

Yellow,  garnet. 

K 

5-8 

2-5" 

360° 

Yellow,  blue. 

H-3752 

6-9-8* 

3-5" 

104° 

Triple 

59" 

About  6'  from  (a)  is  H.  3780,  a  multiple  star,  Mg.  7-8-9-8  £, 
a  beautiful  cluster  for  small  telescopes. 

Note  R.,  a  celebrated  variable,  "  Hind's  crimson  star."  At  its 
minimum  it  is  intensely  red  in  color.  Hind  describes  it  as 
resembling  a  blood  drop  on  the  background  of  the  sky.  As 
regards  depth  of  color  no  other  star  visible  in  these  latitudes 
can  be  compared  with  it.  Its  period  is  about  436  days.  At 
maximum  its  magnitude  is  6  to  7,  at  minimum  8. 

"Its  spectrum  indicates  that  it  is  smothered  with  absorbing 
vapors,  a  sun  near  extinction,  which  at  intervals  experiences  an 
accession  of  energy  and  bursts  through  its  stifling  envelope  with 
explosive  radiance,  only  to  faint  and  sink  once  more.  " 

Observe  the  cluster  1112,  "A  splendid  globular  cluster  dis- 
covered by  Mechain  which  Messier  described  as  a  starless 
nebula  with  a  brilliant  centre.  .Herschel  was  the  first  to  resolve 
this  nebula  into  stars.  It  appears  from  photographs  taken  that 
five  stars  out  of  the  two  hundred  of  this  cluster  are  variable.  " 


76 


LEPUS 


Oriou 


••::    o 
H3752 

Orion  Page  81 

Canis  Major   Page  71 
Eridanus         Page  73 


77 


MONOCEROS 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

II 

5-6-7 

7" 

131° 

One  of  the   finest 

Triple 

9" 

124° 

sights     of     the 

heavens. 

4 

6—  10—  ii 

3-4" 

I780 

Triple 

10" 

244° 

8 

5-7 

14" 

24° 

Golden,  blue. 

2921 

64-8 

16* 

4° 

21183 

5^-8 

31* 

326° 

29 

6-9  $-9 

3i/; 

105° 

Triple 

67" 

245° 

31 

5*-8 

78" 

308° 

Yellow,  blue. 

Note  the  cluster  1424,  visible  to  the  naked  eye,  and  very 
beautiful.  Also  1637,  fairly  large  and  crowded  with  stars  of 
the  ninth  magnitude,  including  a  pretty  double. 

There  is  a  glorious  low  power  field  about  (8).  Observe  the 
fine  orange  color  of  (5). 

(n)  was  discovered  in  1781. 


MONOCEROS 


'OS  921 


Procyon 


Betelgeuze 


Siriui 


Orion  Page  81 

Canis  Major  Page  71 
Gemini  Page  75 

79 


ORION 


DOUBLE 
STAR 

MAGNI- 
TUDES 

DISTANCE 

ANGLE 

REMARKS 

5 

2-7 

53" 

360° 

White,  blue. 

I 

3-7 

II* 

142° 

Fine  field. 

X 

3i-6 

4" 

43° 

Yellow,  red. 

Whole       region 

fine. 

p 

5-81 

7" 

62° 

Yellow,  blue. 

f 

2-6-10 

2-5" 

149° 

Yellow,  blue. 

Triple 

56" 

8° 

2747 

5i-6J 

36" 

223° 

28i6 

6i-8| 

4" 

289° 

2627 

6f-7 

2l" 

260° 

A  splendid  pair. 

m 

5-7 

31" 

284° 

Green,  white. 

(23) 

Fine  coloring. 

2855 

6-7 

29» 

H3° 

A    third    star    in 

field. 

02 

5-7-8 

39" 

204° 

A     beautiful     ob- 

Triple 

54" 

88° 

ject. 

2795 

6-6 

1-7" 

200° 

Excellent  test. 

2750 

6-8 

4" 

59° 

2725  and  ^  have  eleventh  magnitude  companions. 

(<r)  is  a  beautiful  multiple  star,  and  is  a  colored  variable,  (e) 
and  (j3)  are  receding  from  the  earth  at  the  rate  of  35  and  39 
miles  per  second  respectively;  (a)  at  the  rate  of  28  miles  per 
second. 

Proctor  says  a  three-inch  glass  should  show  the  ninth  magni- 
tude companion  to  Rigel.  D.,  9",  A.,  199°.  Smyth  claims 
it  is  a  test  for  a  four-inch  glass. 

Words  fail  to  describe  the  great  nebula  1179.  Its  glories 
must  be  seen  to  be  appreciated.  A  three-inch  glass  will  show 
the  four  stars  forming  the  trapezium  in  the  nebula.  The  whole 
region  about  the  nebula  is  rich  in  doubles,  triples,  and  multiple 
stars.  The  nebula  has  been  under  effective  observation  for 
244  years.  It  is  the  most  conspicuous  and  interesting  object 
of  its  kind  in  the  northern  heavens.  It  is  receding  from  the 
earth  at  the  rate  of  1 1  miles  per  second,  which  is  about  the  sun's 
computed  velocity  through  space  in  the  opposite  direction. 
Hence  the  nebula  is  probably  at  rest. 

80 


W  1361        / 

:';  1383 


ORION 


-905 


Betelgeuze 


Bellatriz 


2816 


2856 


S827 


Eridanus  Page  73 
Gemini  Page  75 
Taurus  '  Page  67 


Lepus         Page  77 
Monoceros  Page  79 


Si 


THE  MOON 


THE  DIAGRAMS  OF  THE  MOON 

THESE  are  sketches  from  a  series  of  fine  photographs 
that  recently  appeared  in  Mr.  Garrett  P.  Serviss's 
excellent  book  entitled  The  Moon.  They  are  only  in- 
tended to  guide  the  student  in  the  identification  of  the 
lunar  wonders  visible  in  a  three-inch  telescope,  and  make 
no  claim  to  exactness  or  pictorial  resemblance. 

The  mean  distance  of  the  moon  from  the  earth  is 
238,818  miles.  Its  diameter  is  2163  miles,  and  it  is  a 
little  larger  than  the  continent  of  South  America.  Be- 
cause of  the  moon's  comparative  proximity  to  the  earth, 
it  is  the  easiest  and  most  interesting  of  telescopic  ob- 
jects, especially  to  the  owner  of  a  small  telescope. 

A  telescope  which  magnifies  only  one  hundred  times 
will  show  a  spot  on  the  moon's  surface  whose  diameter 
is  1223  yards.  One  which  magnifies  a  thousand  times 
will  enable  us  to  perceive  objects  on  her  surface  whose 
dimensions  are  only  122  yards,  which  does  not  much 
exceed  the  size  of  the  Capitol  at  Washington.  The 
highest  power  yet  applied  to  the  moon,  a  power  of  six 
thousand,  brings  her  to  an  apparent  distance  of  forty 
miles. 

No  object  that  could  with  the  slightest  appearance  of 

85 


86  The  Moon 

probability  be  ascribed  to  the  labors  of  intelligent  crea- 
tures has  ever  been  detected  on  the  moon's  surface. 

We  know  more  of  the  physical  formation  of  the  face 
of  the  moon  turned  toward  us,  than  we  know  of  certain 
parts  of  Asia,  South  America,  and  the  interior  of  Africa. 

More  than  five  hundred  features  of  the  lunar  surface 
have  received  names.  Water  cannot  possibly  exist  as  a 
liquid  on  the  moon,  for  the  temperature  of  the  moon's 
surface  during  the  long  lunar  night  is  probably  not  far 
from  460  degrees  below  the  zero  mark  on  a  Fahrenheit 
thermometer. 

The  light  of  the  full  moon,  which  equals  the  light  of 
100,000  stars  of  zero  magnitude,  is  one-6i8,oooth  part  of 
the  sun's  light,  and  about  twelve  times  the  light  of  the 
half  moon.  The  moon  reflects  about  one-tenth  of  the 
light  which  falls  on  it  from  the  sun.  In  the  whole  heav- 
ens the  stars  give  about  one-eightieth  as  much  light  as 
the  full  moon.  The  earth  reflects  to  the  moon  about 
fourteen  times  as  much  light  as  the  moon  sends  to  the 
earth. 

It  is  best  to  observe  the  moon  with  a  low  power,  and 
under  the  varying  conditions  of  sunrise  and  sunset, 
"  which,  like  the  corresponding  times  of  the  earth,  abound 
with  grand  and  beautiful  effects  of  light  and  shade." 

The  best  view  of  an  object  on  the  moon's  surface  is  to 
be  had  when  it  is  on  the  terminator,  as  the  boundary  line 
between  the  illuminated  and  the  unilluminated  portions 
of  the  moon  is  called.  Those  objects  which  are  on  the 


The  Moon  87 

terminator  early  during  the  first  quarter,  will  be  found 
there  early  on  the  third  quarter. 

The  occultation  of  a  star  by  the  moon  is  an  interesting 
sight,  and  one  that  can  be  well  observed  by  the  owner  of 
a  small  telescope.  All  occultations  of  importance  are 
predicted  in  the  nautical  almanac.  The  instantaneous 
disappearance  and  reappearance  of  the  star  occulted 
is  the  striking  feature  of  this  event.  The  nautical  alma- 
nac should  be  in  the  hands  of  every  amateur  astronomer. 
It  is  published  several  years  in  advance,  and  can  be 
obtained  of  the  Superintendent  of  Documents  in  Washing- 
ton at  small  cost. 

A  partial  list  of  occultations  which  occur  at  favorable 
times  for  observation,  up  to  January  i,  1911,  will  be 
found  on  page  106. 

Although  the  general  statement  is  true  that  we  see 
only  half  of  the  moon,  to  speak  more  correctly  we  see 
about  fifty-nine  per  cent,  of  the  moon's  surface,  although 
we  never  see  this  amount  at  any  one  time.  This  fact  is 
due  to  the  "balancings"  or  libration  of  the  moon,  as  it 
is  called.  The  student  is  advised  to  consult  an  astron- 
omy for  a  further  discussion  of  this  subject,  as  the  treat- 
ment of  technical  matters  does  not  come  within  the  scope 
of  this  book. 

Because  of  the  phenomena  of  libration,  it  is  impossible 
to  give  a  fixed  position  to  the  various  formations  on  the 
moon's  surface  with  respect  to  the  moon's  age,  so  that  no 
precise  instructions  can  be  given  where  to  look  for  them. 


88  The  Moon 

The  nomenclature  of  the  moon  is  interesting  because 
it  serves  to  immortalize  the  names  of  many  of  the  wise 
men  of  old  whose  memory  would  otherwise  sink  into 
oblivion.  The  astronomer  Riccioli  of  Bologna,  who  pub- 
lished a  chart  of  the  moon  in  1650,  is  responsible  for  most 
of  the  names  of  the  interesting  features  of  the  moon's 
surface,  and  many  of  them  are  fanciful  beyond  reason. 

The  fact  that  seems  to  impress  most  persons  who  view 
the  moon  for  the  first  time  through  a  telescope  is  the 
rapidity  with  which  it  passes  out  of  the  field  of  vision. 
The  high  magnification  emphasizes  the  earth's  motion 
to  such  an  extent  and  the  speed  with  which  we  are  trav- 
elling is  thus  made  manifest  in  such  a  startling  way,  that 
few  gaze  without  expressing  their  astonishment.  Then, 
too,  the  detail  brought  out  by  even  a  low  power  is  a 
matter  of  wonder.  It  seems  almost  incredible  that  in  a 
small  telescope  craters  on  the  moon  only  six  miles  in 
diameter  can  be  seen  distinctly. 

Only  a  portion  of  what  appears  on  the  earlier  diagrams 
is  repeated  in  the  successive  views,  as  their  repetition 
would  tend  to  fill  up  the  diagram  with  names  leading  to 
confusion.  In  each  diagram  therefore,  particular  stress 
is  laid  on  the  additional  features  of  the  moon's  surface 
that  the  ever-advancing  sunlight  reveals. 

The  word  crater  is  used  in  connection  with  the  great 
ringed  depressions,  surrounded  by  mountains,  that  are 
so  numerous  on  the  moon's  surface.  It  is  a  misnomer  as 
applied  to  these  formations  which  are  totally  unlike  ter- 


The  Moon  89 

restrial  craters.  No  doubt  they  are  of  volcanic  origin, 
but  here  the  analogy  ceases.  Nothing  on  the  earth  is 
like  them.  Ringed  plains  is  perhaps  the  best  name  for 
them,  as  it  is  descriptive  in  a  measure.  They  are  like 
great  amphitheatres,  sometimes  100  miles  in  diameter, 
surrounded  by  gigantic  mountain  walls  that  rise  almost 
abruptly  thousands  of  feet  high.  They  often  contain  a 
central  mountain,  or  a  bowl-like  pit. 

The  lunar  landscape  is  all  on  a  stupendous  scale.  It  is 
said  that  there  are  twenty-eight  peaks  on  the  moon  that 
exceed  in  height  our  most  lofty  mountains.  Everywhere 
on  the  moon's  surface  are  traces  of  cataclysmic  action 
that  is  almost  beyond  our  comprehension. 

In  conclusion,  the  diagrams  of  the  moon  represent  its 
telescopic  or  inverted  appearance,  so  that  the  north 
point  is  at  the  bottom,  the  south  at  the  top,  the  east 
to  the  right,  the  west  to  the  left  side  of  the  diagrams 
respectively. 


MOON— PLATE  I 

The  narrow  crescent  of  the  moon  illumined  by  the  sun,  as 
shown  in  the  opposite  plate,  presents  few  objects  of  interest  to 
the  observer,  but  as  each  successive  night  of  observation  until 
the  moon  is  full  presents  new  material  worthy  of  attention,  it 
is  well  for  the  student  to  master  the  details  as  they  are  pre- 
sented. 

The  Mare  Crisium.  or  the  Sea  of  Crises  or  Conflicts,  as  it  is 
called,  is  the  most  prominent  object  visible  at  this  time,  and 
because  of  its  dark  hue  the  analogy  to  a  sea  is  striking.  It  meas- 
ures 350  miles  from  north  to  south,  280  miles  from  east  to 
west.  Note  Cape  Agarum,  11,000  ft.  high,  jutting  out  into  the 
sea  on  the  southwest,  and  two  small  craters  on  the  surface  of 
the  sea's  floor  a  little  east  of  its  centre.  The  southern  one  is 
named  Picard,  the  northern  Pierce. 

North  of  the  Mare  Crisium  is  the  crater  Cleomedes.  It  is 
80  miles  in  diameter.  One  peak  on  its  wall  is  10,000  feet  high 
and  it  contains  a  central  mountain  divided  by  three  clefts. 
On  its  eastern  wall  is  a  very  deep  crater  named  Tralles. 

If  the  atmospheric  conditions  are  favorable,  a  certain  amount 
of  detail  can  be  seen  on  the  dark  or  earthlit  portion  of  the  moon. 
The  brilliant  crater  Aristarchus,  and  the  darkest  crater,  Grimaldi, 
on  the  eastern  limb  of  the  moon,  have  been  seen. 


90 


w 


PLATE  I 
Moon's  Age  3.85  Days 

s 


E 


N 


MOON— PLATE  II 

Petavius  is  one  of  the  finest  objects  on  the  moon.  It  measures 
ico  miles  from  north  to  south.  Its  wall  is  divided  by  many 
valleys,  while  in  the  centre  of  its  vast  plain  rises  a  mountain 
5600  feet  high.  A  straight  line  radiates  from  this  mountain, 
extending  southeast  to  the  wall  of  the  crater.  This  line,  which 
in  reality  is  a  great  cleft,  one  of  many  on  the  moon's  surface, 
can  be  easily  seen  in  a  three-inch  glass.  The  best  time  to  view 
it  is  a  day  or  so  after  the  full  moon,  when  the  sun  is  setting 
on  the  western  limb  of  the  moon.  In  formation  these  clefts 
or  rills,  as  they  are  called,  are  analogous  to  our  western  canyons. 
Petavius  is  especially  noteworthy  because  of  the  convexity  of  its 
floor,  the  centre  of  which  is  800  feet  higher  than  its  edges. 

Langrenus  is  90  miles  in  diameter.  It  contains  a  mountain 
peak  5800  feet  high.  Note  three  small  craters  just  northeast 
of  Langrenus  forming  a  triangle. 

Vendelinus  is  pear-shaped,  and  therefore  easily  identified. 
Note  a  small  but  brilliant  crater  on  the  northeastern  slope 
of  Furnerius. 

Burckhardt  is  the  name  of  the  crater  just  north  of  Cleomedes. 
North  of  it  is  Geminus,  54  miles  in  diameter.  Its  western  wall 
rises  to  a  height  of  16,700  feet. 

Gauss,  from  north  to  south,  measures  no  miles. 


92 


PLATE  TI 
Moon's  Age  3.87  Days 


w 


N 


93 


MOON— PLATE  III 

The  diamond-shaped  Sea  of  Fecundity  and  the  Sea  of  Nectar, 
pentagonal  in  form,  are  now  visible.  At  the  south  of  the  latter 
sea,  note  Frascatorius  with  its  north  wall  broken  down.  Endy- 
mion  near  the  western  limb  is  elliptical  in  appearance.  Its  west 
wall  in  places  is  15,000  ft.  high.  View  Endymion  3  d.  7  h.  after 
the  new,  and  2  d.  9  h.  after  the  full  moon. 

N.  W.  of  Fabricius  and  Metius  is  a  deep  cleft.  On  the  tip  of 
the  southern  horn  of  the  moon  the  peaks  of  the  Leibnitz  Mts. 
may  be  seen. 

Messier,  9  m.  across,  and  Messier  A  are  noteworthy.  Two 
slightly  diverging  streaks  run  east  from  the  latter  for  a  long  dis- 
tance. They  seem  artificial,  but  their  character  is  still  an 
enigma. 

Alleged  changes  have  taken  place  in  the  shape  of  these  craters. 

East  of  Proclus  is  a  peculiar  yellowish-brown  patch  somewhat 
diamond-shaped.  It  is  called  Palus  Somnii,  or  "Marsh  of  a 
Dream." 

Hercules  and  Atlas  are  best  viewed  5  or  6  days  after  the  new 
moon,  or  3^  days  after  the  full  moon.  The  former  contains  a 
crater  pit,  and  is  46  m.  across.  In  the  centre  of  Atlas,  which  is 
55  m.  in  diameter,  rises  a  mountain. 


94 


w 


PLATE  III 

Moon's  Age  5.54  Days 
S 


E 


N 


95 


MOON— PLATE  IV 

Note  the  crooked  line  of  the  Altai  Mts.  and  the  Taurus  and 
Haemus  ranges,  with  Pliny  32111.  across,  between  them.  Dawes 
lies  just  west  of  Pliny. 

East  of  the  Sea  of  Nectar  is  a  striking  group,  Theophilus, 
Cyrillus,  and  Catharina.  The  former  is  64  m.  across.  Its  wall 
in  places  is  18,000  ft.  high.  Its  central  peak  can  be  seen  beyond 
the  terminator  5  d.  after  the  new  moon.  Cyrillus  is  trapezoidal 
in  form  and  contains  two  peaks.  The  N.  W.  portion  of  its 
wall  has  been  demolished  to  make  way  for  the  wall  of  Theophilus. 

Posidomus  on  the  western  shore  of  the  Sea  of  Serenity  is  62  m. 
across  and  contains  a  crater.  Its  interior  plain  lies  about  2000 
ft.  below  the  outer  surface  of  the  moon.  It  is  best  viewed  6  d. 
after  the  new  moon.  North  of  it  is  a  "V  "  shaped  bay  called  the 
Lacus  Somniorum  or  "Lake  of  Sleepers."  A  peculiar  ridge 
winds  its  way  from  Posidonius  to  Pliny  across  the  Sea  of  Seren- 
ity. South  of  Posidonius  is  Le  Monnier  with  its  eastern  wall 
broken  down. 

Mt.  Argaeus,  N.  W.  of  Pliny,  8400  ft.  high,  is  a  fine  sight 
when  the  moon  is  5  d.  old. 

North  of  the  Sea  of  Nectar  note  Isidore  and  Capella  with  a 
peak  over  13,000  ft.  high  between  them.  The  ring  of  Capella  is 
cut  down  by  a  broad  cleft. 

N.  E.  of  the  Mare  Crisium  note  Vitruvius,  Maraldi,  Littrow 
and  Roemer. 

South  of  Fabricius  and  Metius  are  three  small  craters  close  to- 
gether, Pitiscus,  Hcmmel,  and.Valcq.  Steinheil,  N.  W.  of  them, 
is  shaped  like  the  figure  "  8  ".  Polybius  and  Pons  lie  on  opposite 
sides  of  the  Altai  Mts. 


PLATE  IV 
Moon's  Age  5.74  Days 
S 


N 


97 


MOON— PLATE  V 

In  the  south  Maurolycus,  150  m.  across,  and  Stafler  are  con- 
spicuous. The  former  is  best  viewed  about  the  time  of  the  moon's 
first  quarter.  At  full  moon  it  is  practically  invisible.  Some 
of  its  peaks  are  15,000  ft.  high. 

About  the  centre  of  the  moon,  just  west  of  the  terminator,  lie 
Albategnius,  65  m.  across,  and  north  of  it  Hipparchus,  90  m. 
in  diameter.  The  latter  exhibits  signs  of  demolition  and  is 
presumably  older  than  Albategnius  which  is  very  deep  and  com- 
paratively perfect. 

Note  Menelaus  and  Sulpicius  Gallus  on  the  south  shore  of  the 
Sea  of  Serenity,  with  Manilius  between  them.  It  is  not  known 
why  these  and  a  few  other  craters  are  so  conspicuously  bright. 

The  Caucasus  Mts.  are  prominent  south  of  Eudoxus  and  Aris- 
toteles  (50  m.  across).  In  the  centre  of  the  range  is  Calippus. 

The  dotted  line  across  the  Sea  of  Serenity  represents  a  light 
streak  radiating  from  Tycho,  2000  m.  to  the  southward.  It 
crosses  Bessel,  14  m.  in  diameter,  situated  in  the  midst  of  the 
Sea  of  Serenity.  The  character  of  the  light  streaks  on  the  moon 
is  unknown. 

The  small  triangular  shaped  crater  east  of  the  Caucasus  Mts. 
is  Thesetetus,  interesting  because  a  French  observer  claims  to 
have  seen  smoke  rising  near  it. 

The  Sea  of  Serenity  is  430  m.  long  and  about  as  wide.  Its 
area  is  125,000  sq.  m. 

Godin,  23  m.,  and  Agrippa,  27  m.  in  diameter,  respectively, 
are  fine  objects  when  seen  on  the  terminator.  A  minute  point 
of  light  is  alleged  to  have  been  seen  near  them. 

S.  E.  of  Piccolomini  are  three  craters  forming  a  triangle. 
Zagut  is  the  name  of  the  largest. 


98 


PLATE  V 
Moon's  Age  7.75  Days 


N 


99 


MOON— PLATE  VI 

Clavius  is  conspicuous  in  the  south.  It  is  140  m.  across,  16,000 
sq.  m.  in  area,  and  a  peak  on  its  western  wall  is  17,300  ft.  high. 
Withki  its  walls  go  craters  have  been  counted.  If  its  surround- 
ing wall  were  straight,  it  would  cover  the  distance  from  New  York 
to  Buffalo. 

Tycho,  54  m.  in  diameter,  is  the  perfectly  formed  crater 
north  of  Clavius.  A  system  of  light  streaks  extending  over  a 
quarter  of  the  visible  hemisphere  of  the  moon  radiate  from  it. 

North  of  Tycho,  just  west  of  the  terminator,  lie  two  groups 
containing  three  craters  each.  The  largest  in  each  group  lies 
to  the  north. 

The  Apennine  Mts.,  a  grand  range,  start  from  Mt.  Hadley, 
15,000  ft.  high,  and  terminate  at  Eratosthenes  450  m.  to  the 
S.  E. 

Eratosthenes,  38  m.  across,  is  8000  ft.  deep.  It  contains 
three  conspicuous  central  peaks. 

Archimedes,  50,  Autolycus,  23,  and  Aristillus,  34  m.  in  diam- 
eter respectively,  lie  north  of  the  Apennines.  Cassini,  to  the 
north  of  them,  contains  two  central  pits.  More  than  fifty 
objects  have  been  detected  within  the  walls  of  Archimedes. 

Note  the  small  peak  Linne  north  of  Mt.  Hadley.  Alleged 
changes  have  been  noted  in  its  form. 

The  Alps  are  pierced  by  a  great  cleft  80  m.  long  and  from 
3i  to  6J  m.  in  width.  Its  depth  is  at  least  11,500  ft. 

Ariada3us  is  connected  with  Hyginus  by  a  valley  best  observed 
at  first  quarter.  Hyginus  is  situated  on  the  western  shore  of 
the  Mare  Vaporum  or  "Sea  of  Mists." 

Note  the  Sinus  ^Estuum,  or  "Gulf  of  Heats,"  south  of  the 
Mare  Vaporum. 


PLATE  VI 
Moon's  Age   9.22  Days 


W 


N 

101 


MOON— PLATE  VII 

Note  Cichus,  north  of  Tycho.  A  crater  on  its  eastern  wall 
only  6  m.  across  can  be  seen. 

West  of  Birt  note  the  Lunar  Railway  or  Straight  Wall,  a 
cliff  line  65  m.  long  and  1000  ft.  high,  best  viewed  one  or  two  days 
after  the  first  quarter.  The  western  shore  of  the  Mare  Nubium, 
or  "Sea  of  Clouds,"  outlines  the  profile  of  the  "old  lady  in  the 
moon."  Her  hooked  nose  is  just  S.  E.  of  Ptolemy.  Note 
Bulliadus  38  m.  across,  and  9000  ft.  deep,  and  Gassendi,  55  m. 
in  diameter.  There  are  many  curious  clefts  in  the  wall  of 
Gassendi.  North  of  it  is  Letronne,  its  north  wall  broken  down. 

Copernicus  is  conspicuous.  It  contains  8  central  peaks,  3  of 
which  are  bright  ones,  and  one  is  2400  ft.  high. 

Plato,  60  m.  across,  is  one  of  the  darkest  spots  on  the  moon. 
Hevelius  called  it  "the  great  black  lake."  South  of  it  note 
Pico  8000  ft.  high. 

Capes  Heraclides  and  La  Place  are  at  the  eastern  and  western 
extremities  respectively  of  the  Sinus  Iridum  or  "Bay  of  Rain- 
bows." They  are  135  m.  apart.  The  former  is  4000  ft.  high,  and 
its  shadow  forms  the  silhouette  of  the  "moon  maiden,"  best 
viewed  when  the  moon  is  1 1  days  old. 

The  Carpathian  Mts.  north  of  Copernicus  are  best  viewed  10 
days  after  the  new  moon.  East  of  them  is  Tobias  Mayer,  20  m. 
across  and  9700  ft.  deep.  Kepler,  22  m.  across,  is  notably 
bright. 

Newton,  south  of  Clavius,  is  142  m.  long  and  24,000  ft.  deep, 
the  deepest  crater  on  the  moon. 

Note  the  circular  Mare  Humorum  or  "Sea  of  Humors,"  the 
darkest  of  the  seas. 


102 


W 


PLATE  VH 

Moon's  Age  11.78  Days 

s 


E 


N 
103 


MOON— PLATE  VIII 

The  telescopic  view  of  the  full  moon,  contrary  to  the  popular 
notion,  is  disappointing.  The  brilliancy  of  the  reflected  light 
dazzles  the  eye,  eliminates  the  shadows  of  the  great  peaks,  and 
renders  the  interesting  details  invisible. 

Grimaldi  on  the  eastern  limb,  148  m.  long  by  129  m.  broad,  is 
the  darkest  spot  on  the  moon.  N.  W.  of  it  in  the  Oceanus 
Procellarum  or  "Ocean  of  Tempests"  is  Aristarchus,  the  bright- 
est spot  on  the  moon.  It  is  28  m.  across  and  connected  with 
Herodotus  by  a  short  bright  ray. 

Herodotus  is  24  m.  across.  A  winding  valley  starts  from  it 
and  can  be  traced  across  the  sea  for  a  distance  of  TOO  m. 

Note  the  dark  patches  west  of  Copernicus,  the  color  of  the 
Palus  Somnii,  the  brilliant  craters  Proclus,  Ariadaeus,  Menelaus, 
Manilius,  Sulpicius  Callus,  Pico,  Aristarchus,  and  the  black 
craters  Plato  and  Grimaldi. 

Observe  the  Riphaean  Mts.  north  of  the  Mare  Humorum,  and 
the  Harbinger  Mts.  north  of  Aristarchus.  The  dark  patch 
north  of  the  Mare  Imbrium,  -extending  from  the  Caucasus  Mts. 
to  the  Oceanus  Procellarum,  is  the  Mare  Frigoris,  or  "Sea  of 
Cold."  The  bay  that  seems  to  connect  the  Mare  Frigoris  with 
the  Oceanus  Procellarum,  north  of  the  Bay  of  Rainbows,  is 
the  Sinus  Roris,  or  "Gulf  of  Dews."  Archimedes,  Autolycus,  and 
Aristillus  are  surrounded  by  an  area  of  a  lighter  hue  than  that 
of  the  Mare  Imbrium.  This  region  is  called  "The  Marsh  of 
Corruption." 

All  the  southern  and  western  portions  of  the  moon  are  wanting 
in  detail,  owing  to  the  intensity  of  the  light. 


104 


PLATE  VIII 
Moon's  Age  14.40  Days 


W 


E 


N 
105 


OCCULTATIONS    BY  THE  MOON  VISIBLE  AT  WASH- 
INGTON, D.  C.,  AT  CONVENIENT  HOURS  FOR 
OBSERVATION 

FROM  SEPT.  i,  1909,  TO  JAN.  i,  1911 


DATE 

STAR  OR 
PLANET 

MAGNI- 
TUDE 

DISAPPEAR- 
ANCE 

DURATION 

1909 

h. 

m. 

h. 

m. 

Sept.     i 

Mars 

8 

42 

57 

3 

£  Arietis 

5-5 

9 

28 

8 

29 

26  Ceti 

6 

7 

41 

59 

Oct.      20 

ff  Sagittarii 

2-3 

7 

i 

59 

24 

69  Aquarii 

5-6 

8 

8 

I 

I7 

24 

T  Aquarii 

4-4 

9 

4i 

I 

6 

Nov.    19 

3  7  Capricorni 

5-7 

8 

36 

59 

23 

33  Ceti 

6.1 

8 

58 

I 

14 

Dec.    22 

31  Arietis 

5-7 

7 

18 

46 

1910 

Jan.     20 

53  Tauri 

5-3 

10 

31 

I 

14 

"        26 

77  Leonis 

3-6 

9 

29 

I 

12 

Feb.    19 

40  Geminorum 

6-3 

8 

7 

48 

Mar.    1  6 

T  Tauri 

4-5 

7 

26 

I 

14 

Apr.    12 

56  Tauri 

S-2 

7 

12 

I 

I 

Aug.    10 

m  Virginis 

5-4 

8 

35 

I 

I 

Nov.   17 

95  Tauri 

6.2 

9 

59 

30 

The  time  given  for  the  occultations  is  the  mean  time 
at  Washington,    D.   C.     It   is    necessary  for  observers 

106 


Occultations  by  the  Moon  107 

elsewhere  to  correct  the  time  to  suit  their  respective 
locations.  The  longitude  of  Washington  is  west  of 
Greenwich  5  hours  8  minutes  15.78  seconds. 

The  list  given  is  only  a  partial  one,  and  the  student 
should  consult  the  nautical  almanac  for  the  complete 
list. 

The  most  beautiful  occult ations  are  those  when  the 
star  disappears  behind  the  dark  limb  of  the  moon  as 
between  new  moon  and  first  quarter. 

Because  of  the  moon's  eastward  motion  relatively 
to  the  stars,  the  disappearances  when  viewed  with  the 
naked  eye  will  take  place  on  the  eastern  or  left-hand  limb 
of  the  moon,  the  reappearances  on  the  western  or  right- 
hand  limb.  The  reverse  is  true  when  the  occultation  is 
viewed  through  a  telescope. 


THE  PLANETS 


109 


THE  PLANETS 

IN  addition  to  the  multitude  of  interesting  objects  con- 
nected with  the  universe  of  stars,  there  are  the  planets 
of  our  own  system  to  be  observed,  and  because  their 
comparative  proximity  renders  them  more  satisfactory 
objects  to  view  in  a  small  telescope,  they  are  of  greater 
interest  to  the  amateur  astronomer  than  those  great 
suns  that  send  us  at  best  but  faint  messages  of  light,  and 
concerning  which  our  knowledge  must  for  obvious 
reasons  be  largely  conjectural. 

The  amateur  astronomer  with  his  three-inch  glass  has 
in  the  observation  of  the  planets  a  source  of  pleasure 
that  can  never  wane.  Their  numerous  changes  in  posi- 
tion add  variety  to  the  observations,  and  their  near 
approaches  to  the  earth  lend  the  zest  of  anticipation  to 
the  interested  student. 

There  is  the  greatest  satisfaction  in  seeing  with  your 
own  eyes  the  peculiar  characteristics  of  the  planets  that 
our  own  sun  illumines,  of  which  volumes  have  been  writ- 
ten and  which  the  whole  race  of  intelligent  beings  have 
wondered  at.  Much  more  can  be  seen  with  a  small  tele- 
scope than  is  imagined,  and.  the  sight  of  the  satellites 
of  Jupiter  and  the  rings  of  Saturn  is  far  more  impressive 


ii2  The  Planets 

and  satisfactory  than  any  amount  of  reading  concerning 
them. 

As  this  book  is  properly  a  hand-book,  or  a  ready  refer- 
ence for  the  use  of  the  observer,  it  is  only  necessary 
to  call  attention  briefly  to  what  can  be  observed  of  the 
planets  with  the  optical  power  at  our  command.  Taking 
up  the  planets  in  order,  counting  from  the  sun  outward, 
the  planet  Mercury  first  claims  our  attention. 

MERCURY 

So  few  have  ever  seen  Mercury  that  even  the  very  sight 
of  that  planet  in  an  opera-glass  is  a  source  of  satisfaction. 
The  fact  that  it  never  reaches  in  its  orbit  a  distance  of 
more  than  28  degrees  from  the  sun,  and  that  it  is  never 
visible  for  more  than  two  hours  after  sunset  or  before 
sunrise,  according  as  it  follows  or  precedes  the  sun, 
accounts  for  the  fact  that  it  is  so  seldom  seen. 

The  best  time  for  searching  for  it  is  when  it  is  farthest 
east  or  west  of  the  sun,  a  fact  which  any  good  almanac 
will  furnish.  An  opera-glass,  because  of  its  large  field, 
is  most  useful  in  looking  for  Mercury,  although  if  once 
glimpsed  with  the  naked  eye  the  telescope  readily 
picks  it  up.  In  appearance  it  is  brighter  than  a  first 
magnitude  star,  and  sometimes  it  seems  of  a  reddish  hue. 

The  transits  of  Mercury  across  the  sun's  disk  average 
thirteen  in  every  hundred  years,  and  are  exceedingly 
interesting  events  to  watch  even  with  a  small  telescope. 
The  transits  always  occur  in  the  months  of  May  or 


The  Planets  113 

November.  November,  1907,  was  the  date  of  the  last 
transit,  and  the  next  four  will  occur  November  6,  1914; 
May  7,  1924;  November  8,  1927;  and  May  10,  1937. 

Aside  from  the  satisfaction  of  seeing  Mercury,  a  pleas- 
ure that  was  denied  to  Copernicus  even,  there  is  little  to 
interest  the  amateur  astronomer  save  to  note  the  phases 
that  the  planet  assumes,  which  are  similar  to  those 
of  the  moon.  The  crescent  Mercury  gleaming  in  the 
waning  light  of  the  dying  day,  and  seen  for  the  first 
time  is  a  sight  never  to  be  forgotten. 

VENUS 

Venus,  so  beautiful  to  the  unaided  eye,  is  also  a 
telescopic  disappointment,  for  aside  from  its  phases, 
which  are  always  a  source  of  interest  to  observe,  there  are 
no  surface  features  within  the  range  of  our  optical  power. 

The  planet  is  best  viewed  in  the  twilight  or  just  before 
the  dawn,  when  the  faint  light  of  day  serves  to  deprive 
the  radiant  orb  of  a  portion  of  its  brilliancy.  Seen  under 
these  conditions  the  crescent  Venus  is  one  of  the  most 
beautiful  objects  in  the  heavens.  Of  course  if  the  tele- 
scope is  equatorially  mounted,  both  Venus  and  Mercury 
can  be  seen  in  broad  daylight. 

MARS 

Because  of  the  question  of  the  habitability  of  Mars, 
it  must  ever  be  the  most  interesting  of  the  planets  to 
mankind,  and  the  amateur  astronomer  has  a  never 


n4  The  Planets 

failing  source  of  pleasure  in  the  observation  of  many  of 
the  surface  markings  on  the  planet,  concerning  which 
there  has  been  so  much  discussion.  This  is  especially 
true  when  the  planet  is  nearest  the  earth. 

The  crescent  phase  never  appears  in  planets  which 
revolve  outside  the  earth's  orbit,  but  at  times  Mars 
appears  gibbous  like  the  moon,  when  it  is  three  or  four 
days  from  full. 

At  favourable  oppositions,  which  occur  once  in  fif- 
teen or  seventeen  years,  the  more  conspicuous  dark 
markings,  the  "Hour  Glass"  or  Kaiser  Sea,  and  the 
polar  snow  caps,  can  be  seen  with  our  glass.  The  so- 
called  canals,  concerning  which  there  has  been  so 
much  controversy,  can  only  be  seen  with  the  largest 
telescopes. 

A  power  of  200  is  recommended.  The  presentation 
in  Sept.,  1909,  will  be  most  favorable. 

JUPITER 

Because  of  its  colossal  size,  86,000  miles  in  diameter, 
and  its  brilliancy,  Jupiter  is  probably  the  most  satis- 
factory of  all  the  planets  to  view  in  a  small  telescope ;  for 
in  addition  to  the  markings  on  the  surface  of  the  planet 
which  can  be  easily  seen,  the  rapid  changes  in  the  posi- 
tion of  its  four  principal  satellites  can  be  observed  to 
advantage,  and  ever  prove  a  source  of  pleasure  and 
wonderment. 

A  power  of  1 30  or  thereabouts  should  be  used.    There  is 


The  Planets  115 

no  difficulty  in  seeing  the  two  principal  belts,  and  the 
elliptical  shape  of  the  planet  will  be  at  once  noted. 
It  is  even  possible,  when  the  atmospheric  conditions  are 
favorable,  to  see  the  different  colors  of  the  belts  that 
cross  the  planet  parallel  to  its  equator. 

"A  point  on  Jupiter's  equator  moves  about  27,000 
miles  or  considerably  more  than  the  entire  circumference 
of  the  earth  in  a  single  hour.  The  effect  of  this  motion 
is  clearly  perceptible  to  the  observer  with  a  telescope 
on  account  of  the  diversified  markings  and  colors  of  the 
moving  disk,  and  to  watch  it  is  one  of  the  greatest 
pleasures  that  the  telescope  affords."  The  time  of  rota- 
tion is  four  or  five  minutes  less  than  10  hours.  Jupiter 
would  contain  1389  earths,  and  is  larger  than  all  the 
planets  of  our  system  put  together. 

The  observation  of  the  satellites  of  Jupiter  will  prob- 
ably interest  the  amateur  to  a  greater  degree  even  than 
the  view  of  the  belts. 

The  four  satellites,  visible  in  our  telescope,  are  named 
lo,  Europa,  Ganymede,  and  Callisto,  beginning  with  the 
innermost,  but  they  are  generally  referred  to  as  I,  II,  III, 
and  IV  respectively. 

So  rapid  are  the  changes  in  the  positions  of  the  satel- 
lites that  the  changes  can  be  detected  in  a  few  hours 
of  observation,  and  the  amateur  has  a  chance  to  verify 
the  predictions  as  regards  their  respective  positions  in  the 
ephemeris.  Sometimes  the  four  moons  will  appear  on  one 
side  of  the  planet,  and  again  two  will  appear  on  each  side, 


n6 


The  Planets 


and  this  ever-changing  scene,  that  is  quite  unique  and 
different  from  anything  else  that  human  eyes  behold, 
has  a  fascination  about  it  that  is  peculiarly  its  own. 

The  sight  of  the  eclipses,  occultations,  and  transits  of 
the  satellites,  and  the  transits  of  their  shadows,  is  of  un- 
bounded interest.  The  view  of  transits  of  the  moons  is 
difficult  for  all  save  good  instruments,  but  the  shadows 
in  transit  are  surprisingly  distinct  when  the  air  is  steady. 
The  eclipses  are  accompanied  by  the  phenomena  of 
sudden  disappearance  and  reappearance,  and  are  of  all 
the  phenomena  of  the  satellites  most  interesting  to 
observe. 

THE  SATELLITES  OF  JUPITER  . 


IO 

I 

EUROPA 
II 

GANYMEDE 
III 

CALLISTO 
IV 

Time  of 
revolution 

id.,  i8h. 
28m. 

3d-,  i3h-. 
i4m. 

7d.,  3h., 
43m. 

i6d.,  i6h., 
32m. 

Diameter 

2500 

2100 

3550 

2960 

Mean  dis- 
tance from 
planet 

262,000 

419,000 

664,000 

1,170,000 

Character- 
istics 

Rapid 
Motion 

Largest 
and 
brightest 

Greatest 
orbit 

Colors 

Straw 
color 

White 

Rosy 
orange 

Steel 
gray 

Stellar 
magnitude 

5-28 

5-3i 

4.88 

5-98 

The  Planets  117 

The  diameter  of  our  moon  is  2160  miles. 

To  assist  the  student  in  viewing  the  phenomena  of  the 
satellites  of  Jupiter  a  condensed  portion  of  the  nautical 
almanac  relating  thereto  for  a  brief  time  follows. 

It  has  been  prepared  solely  with  a  view  to  save  the 
student  the  trouble  of  looking  up  the  data  for  himself,  and 
to  excite  his  interest  in  this  fascinating  phase  of  obser- 
vational work. 

The  hours  given  are  all  convenient  for  observation, 
and  the  verification  of  the  predictions,  regardless  of  the 
wonderful  and  beautiful  sight  of  the  rapidly  moving 
satellites,  is  one  of  the  greatest  pleasures  of  the  amateur 
astronomer. 


PHENOMENA  OF  THE  SATELLITES  OF  JUPITER 
VISIBLE  AT  WASHINGTON  AT  THE  TIME  INDI- 
CATED DURING  THE  MONTHS  OF  JULY  AND 
AUGUST,  1909,  AND  THE  YEAR  1910 


DATE 

TIME 

SATELLITE 

PHENOMENA 

1909 

h.     m.      s. 

July    7 

7     57 

I 

Tr.     In. 

7 

9 

I 

Sh.     In. 

7 

9      28 

II 

Sh.     Eg. 

"       8 

8      28      26 

I 

EC.     Re. 

8 

8      43 

IV 

Sh.     In. 

14 

9      16 

II 

Sh.     In. 

23 

8     3°        3 

III 

EC.     Re. 

23 

8     44 

I 

Tr.     Eg. 

30 

8     25 

I 

Tr.     In. 

Aug.    7 

7     4i 

I 

Oc.     Dis. 

"       8 

7     52 

I 

Sh.     Eg. 

8 

7     57 

II 

Tr.     Eg. 

i5 

7     29 

I 

Sh.     In. 

During  the  remainder  of  the  year  Jupiter  is  not  in  a 
favorable  position  for  convenient  observation. 


DATE 

TIME 

SATELLITE 

PHENOMENA 

1910 

Jan.  31 

h.      m.      s. 
ii        4 

I 

Oc.     Re. 

118 


Phenomena  of  Satellites  of  Jupiter  119 


DATE 

TIME 

SATELLITE 

PHENOMENA 

1910 

h.  m.  s. 

Feb.  22 

10  35 

I 

Sh.  In. 

23 

IO     2 

III 

Oc.  Re. 

23 

10   48 

II 

Tr.  Eg. 

"  23 

10  51 

I 

Oc.  Re. 

Mar.  2 

9   9 

II 

Sh.  In. 

2 

g  46  18 

I 

EC.  Dis. 

2 

10  28 

II 

Tr.  In. 

2 

ii   2   56 

III  - 

EC.  Re. 

2 

ii  23 

III 

Oc.  Dis. 

3 

9   13 

I 

Sh.  Eg. 

3 

9  49 

I 

Tr.  Eg. 

10 

8   52 

I 

Sh.  In. 

IO 

g  21 

I 

Tr.  In. 

II 

8  47 

I 

Oc.  Re. 

1  1 

9  59 

II 

Oc.  Re. 

41  18 

8     I    21 

I 

EC.  Dis. 

"  18 

9   i  34 

II 

EC.  Dis. 

18 

10  30 

I 

Oc.  Re. 

I9 

7  45 

I 

Tr.  Eg. 

20 

7  39 

III 

Tr.  In. 

20 

9   i 

III 

Sh.  Eg. 

20 

9  45 

III 

Tr.  Eg. 

"   2"$ 

9   54  54 

I 

EC.  Dis. 

"   26 

7   8 

I 

Sh.  In. 

"   26 

7  i5 

I 

Tr.  In. 

"   26 

9  23 

I 

Sh.  Eg. 

26 

9  29 

I 

Tr.  Eg. 

27 

8  49 

II 

Sh.  Eg. 

27   ' 

8  56 

II 

Tr.  Eg. 

27 

10   25 

III 

Sh.  In. 

27 

10  55 

III 

Tr.  In. 

Apr.  2 

8  59 

I 

Tr.  In. 

2 

9   3 

I 

Sh.  In. 

3 

8  26  56       I 

EC.  Re. 

3 

8  31           II 

Tr.  In. 

120  Phenomena  of  Satellites  of  Jupiter 


DATE 

TIME 

SATELLITE 

PHENOMENA 

IQIO  ' 

h.  m.  s. 

Apr.  3 

8  40 

II 

Sh.  In. 

10 

7  54 

I 

Oc.  Dis. 

10 

10   20   44 

I 

EC.  Re. 

12 

8  49   12 

II 

EC.  Re. 

14 

7   3 

III 

Oc.  Dis. 

14 

10   45   8 

III 

EC.  Re. 

'  18 

7  20 

I 

Sh.  In. 

"  18 

9   8 

I 

Tr.  Eg. 

18 

19 

9  35 

7  5o 

I 
II 

Sh.  Eg. 
Oc.  Dis. 

21 

10   21 

III 

Oc.  Dis. 

25 

8  40 

I 

Tr.  In. 

25 

9   15 

I 

Sh.  In. 

"  26 

8  37  20 

I 

EC.  Re. 

"  26 

10   8 

II 

Oc.  Dis. 

"  28 

8   22 

II 

Sh.  Eg. 

May  2 

8  47 

III 

Sh.  Eg. 

2 

10   26 

I 

Tr.  In. 

3 

7  34 

I 

Oc.  Dis. 

3 

10  31  35 

I 

EC.  Re. 

4 

7  53 

I 

Sh.  Eg. 

5 

8   14 

II 

Sh.  In. 

5 

9   22 

II 

Tr.  Eg. 

5 

10   56 

II 

Sh.  Eg. 

9 

9   17 

III 

Tr.  Eg. 

9 

10   19 

III 

Sh.  In. 

10 

9  21 

I 

Oc.  Dis. 

ii 

7  33 

I 

Sh.  In. 

ii 

8  55 

I 

Tr.  Eg. 

ii 

9  48 

I 

Sh.  Eg. 

12 

9   i 

II 

Tr.  In. 

12 

10  49 

II 

Sh.  In. 

'   14 

8  33   ii 

II 

EC.  Re. 

16 

IO   20 

III 

Tr.  In. 

'  17 

ii   9 

I 

Oc.  Dis. 

18 

8  28 

I 

Tr.  In. 

Phenomena  of  Satellites  of  Jupiter  121 


DATE 

TIME 

SATELLITE 

PHENOMENA 

IQIO 

h.  m.  s. 

May  1  8 

9  28 

I 

Sh.  In. 

18 

10  43 

I 

Tr.  Eg. 

J9 

8  49   4 

I 

EC.  Re. 

25 

10  18 

I 

Tr.  In. 

26 

10  43  40 

I 

EC.  Re. 

27 

8   6 

I 

Sh.  Eg. 

27 

8   22     I 

III 

EC.  Dis. 

27 

10  32   15 

III 

EC.  Re. 

"  28 

3  5i 

II 

Oc.  Dis. 

"  30 

7  59 

II 

Sh.  Eg. 

June  2 

9  16 

I 

Oc.  Dis. 

3 

7  47 

I 

Sh.  In. 

3 

8  5i 

I 

Tr.  Eg. 

3 

IO 

III 

Oc.  Re. 

3 

IO     I 

I 

Sh.  Eg. 

6 

7  53 

II 

Sh.  In. 

6 

8   12 

II 

Tr.  Eg. 

6 

10  34 

II 

Sh.  Eg. 

9 

ii   8 

I 

Oc.  Dis. 

10 

8  28 

I 

Tr.  In. 

10 

9  42 

I 

Sh.  In. 

IO 

10  43 

I 

Tr.  Eg. 

10 

II    IO 

III 

Oc.  Dis. 

1  1 

9   i   51 

I 

EC.  Re. 

"3 

7  59 

II 

Tr.  In. 

J3 

10  29 

II 

Sh.  In. 

J3 

10   42 

II 

Tr.  Eg. 

14 

8  36 

III 

Sh.  Eg. 

15 

8   16  46 

II 

EC.  Re. 

17 

10   21 

I 

Tr.  In. 

18 

10  56  42 

I 

EC.  Re. 

iQ 

8   20 

I 

Sh.  Eg. 

20 

10   31 

II 

Tr.  In. 

21 

10   16 

III 

Sh.  In. 

22 

10   52   42 

II 

EC.  Re 

"   25 

9  23 

I 

Oc.  Dis. 

122  Phenomena  of  Satellites  of  Jupiter 


DATE 

TIME 

SATELLITE 

PHENOMENA 

IQIO 

h.  m.  s. 

June  26 

8 

I 

Sh.  In. 

"  26 

8  59 

I 

Tr.  Eg. 

"  26 

10   15 

I 

Sh.  Eg. 

28 

8  56 

III 

Tr.  In. 

29 

8   16 

II 

Oc.  Dis. 

July  3 

8  39 

I 

Tr.  In. 

3 

9  55 

I 

Sh.  In. 

3 

10  54 

I 

Tr.  Eg. 

4 

9  J5  14 

I 

EC.  Re. 

6 

10  53 

II 

Oc.  Dis. 

8 

10  15 

II 

Sh.  Eg. 

9 

8   19   8 

III 

EC.  Dis. 

9 

10   21   40 

III 

EC.  Re. 

11  10 

10  35 

I 

Tr.  In. 

12 

8  33 

I 

Sh.  Eg. 

"   IS 

10    II 

II 

Sh.  In. 

16 

9  45 

III 

Oc.  Re. 

J7 

7  57   7 

II 

EC.  Re. 

18 

9   4° 

I 

Oc.  Dis. 

I9 

8  14 

I 

Sh.  In. 

I9 

9   17 

I 

Tr.  Eg. 

"  26 

8   59 

I 

Tr.  In. 

27 

8  26 

III 

Sh.  Eg. 

27 

9  28  57 

I 

EC.  Re. 

31 

8   15 

II 

Oc.  Dis. 

Aug.  3 

8   6 

I 

Oc.  Dis. 

3 

8  14 

III 

Tr.  Eg. 

4 

7  42 

I 

Tr.  Eg. 

4 

8  46 

I 

Sh.  Eg. 

9 

7  56 

II 

Tr.  Eg. 

ii 

7  26 

I 

Tr.  In. 

1  1 

8  27 

I 

Sh.  In. 

12 

7  47  34 

I 

EC.  Re. 

"   16 

7  58 

II 

Tr.  In. 

"   18 

7  34   13 

II 

EC.  Re, 

Sept.  3 

7   7 

II    - 

Sh.  Eg. 

Phenomena  of  Satellites  of  Jupiter  123 

During  the  remainder  of  the  year  Jupiter  is  not  in  a  favor- 
able position  for  convenient  observation. 

Abbreviations 

In.  Ingress  EC.  Eclipse 

Eg.  Egress  Oc.  Occultation 

Dis.  Disappearance  Tr.  Transit  of  Satellite 

Re.  Reappearance  Sh.  Transit  of  Shadow. 

The  list  is  taken  from  the  nautical  almanac,  is  but  a 
partial  one,  and  includes  only  the  phenomena  visible 
at  convenient  hours  for  observing. 


Explanation  of  the  Phenomena  cf  Jupiter's  Satellites 


The  student  may  have  some  difficulty  in  understand- 
ing fully  the  phenomena  of  the  satellites  of  Jupiter.  A 
study  of  the  diagram  on  the  opposite  page  will,  it  is 
hoped,  make  the  matter  clear. 

Let  us  suppose  that  Fig.  i  represents  the  view  of 
Jupiter  and  his  moons  in  the  telescope  using  the  celestial 
eyepiece  ; 


ft.01* 


Fig.l 


To  fully  understand  the  real  state  of  affairs  let  us 
consult  Fig.  2.  The  observer  is  supposed  to  be  at  the 
point  on  the  earth's  orbit  marked  "A."  As  the  plane 
of  the  orbits  of  Jupiter's  moons  is  presented  edgewise 
towards  the  earth,  each  moon  appears  to  have  the  motion 
of  a  pendulum  moving  forward  and  back  nearly  in  a 
straight  line.  At  this  precise  time  of  our  observation,  I 
is  between  us  and  the  planet,  and  in  transit.  As  it  is  a 

124 


After,  Opposition 

Satellite  precedes 

Shadow 


Before  Opposition 

Shadow  precedes 

Satellite 


Fig.  2. 

I25 


i26  Explanation  of  the 

bright  object  on  a  bright  background  it  is  practically 
invisible  in  our  glass.  Its  shadow  has  not  quite  ap- 
proached the  point  of  ingress. 

II  is  just  to  the  right  of  the  planet  (the  telescope 
reversing  the  true  state  of  affairs)  and  is  about  to  be 
occulted  by  the  planet.     It  will  be  seen  at  once  that 
on  its  reappearance  from  occultation  it  is  immediately 
eclipsed,  so  that  we  have  it  disappear  in  occultation, 
and  reappear  from  eclipse. 

III  is  also  at  the  right  of  the  planet  and  actually  at 
III  but  appears  at  III'.     Its  shadow  is  in  transit  and  the 
black  dot  of  its  shadow  should  be  seen  on  the  planet. 

IV  is  to  the  left  of  the  planet  and  about  to  be  eclipsed. 

A  careful  study  of  the  diagram  should  enable  the  stu- 
dent to  get  a  correct  idea  of  what  is  taking  place  when  he 
observes  the  planet.  The  nautical  almanac  will  also  be 
found  of  great  assistance  in  making  the  matter  clear. 

SATURN 

Saturn  ranks  next  to  Jupiter  in  presenting  interesting 
features  to  the  possessors  of  small  telescopes. 

The  rings  are  clearly  visible  and  present  a  marvellous 
and  wonderful  appearance.  Its  two  largest  moons,  Titan 
(in  appearance  like  an  eighth  magnitude  star)  and  Japetus, 
can  be  readily  seen,  and  under  good  seeing  conditions, 
Rhea,  Tethys,  and  Dione,  moons  still  nearer  to  the  planet, 
can  be  glimpsed,  but  the  comparatively  sluggish  move- 


Phenomena  of  Jupiter's  Satellites    127 

ments  of  these  attendants  of  Saturn  render  them  unin- 
teresting as  compared  with  those  of  Jupiter.  To  see 
Tethys  and  Dione  the  planet  should  be  screened  from 
view.  It  is  possible  under  favorable  conditions  to  see 
the  belts  on  the  surface  of  the  planet  with  our  glass.  The 
observer  will  at  once  perceive  the  elliptical  appearance 
the  planet,  as  in  the  case  of  Jupiter. 

From  a  combination  of  circumstances,  Saturn  alter- 
nately exhibits  each  side  to  the  earth,  and  the  rings 
appear  to  increase  and  decrease  in  breadth.  This  phenom- 
enon is  gone  through  in  a  little  less  than  fifteen  years  for 
each  side  of  the  rings.  In  1907,  because  of  the  edge 
presentation  of  the  rings,  they  were  invisible  in  a  small 
telescope.  In  a  large  telescope  the  rings  at  such  a  time 
resemble  "  a  pair  of  illuminated  needles  stuck  into  the 
ball  of  the  planet  on  opposite  sides." 

At  present,  1908-9,  the  rings  are  plainly  visible  in  a 
three-inch  glass,  and  in  1915  they  will  be  opened  again  to 
their  widest  extent. 

The  rings  measure  thirty  thousand  miles  across,  and 
are  probably  not  over  one  hundred  miles  in  thickness. 
They  consist  of  an  infinite  number  of  small  bodies 
revolving  about  the  planet  in  a  common  plane.  They 
were  discovered  by  Galileo  in  1610. 

The  two  remaining  planets,  Uranus  and  Neptune,  are 
too  distant  to  offer  any  features  of  interest  to  the  ama- 
teur observer.  Uranus  can  be  seen  very  well  with  a 


128    Explanation  of  Jupiter's  Satellites 

three-inch  glass.  It  is  about  as  bright  as  a  sixth  mag- 
nitude star  and  consequently  can  be  seen  with  the  naked 
eye.  It  will  be  recognized  in  a  telescope  at  once  because 
of  the  absence  of  the  diffraction  ring  which  always  en- 
circles the  star  image  in  a  good  telescope.  The  disk  of 
Uranus  appears  pale  and  diffused,  that  of  a  star  is  sharp 
and  brilliant.  The  almanac  is  indispensable  in  locating 
it.  Light  from  Uranus  takes  2  hours  and  28  minutes  to 
reach  the  earth. 

In  a  three-inch  glass  with  a  power  of  250,  Neptune 
looks  something  like  an  eighth  magnitude  star. 

It  would  take  a  cannon  shot  500  years  to  traverse  the 
orbit  of  Neptune  from  side  to  side,  speeding  continually 
at  its  customary  velocity.  The  nearest  star  is  thousands 
of  times  farther  distant  from  the  earth  than  is  Neptune. 


THE  ECLIPTIC,  SHOWING  THE  POSITIONS  OF 
SATURN,  JUPITER,  AND  MARS,  JANUARY 
FIRST,  FOR  TWELVE  YEARS. 

The  dates  on  the  upper,  middle,  and  lower  lines  indi- 
cate the  positions  of  Saturn,  Jupiter,  and  Mars  respec- 
tively. 

The  movement  is  from  right  to  left. 


130 


PLANETARY  DATA 


PLANET 

DISTANCE 
FROM    SUN   IN 
MILLIONS     OF 

DIAMETER  IN 
THOUSANDS 
OF    MILES 

PERIOD    OF 
REVOLUTION 
ABOUT  SUN 

PASSES 
THROUGH 
ONE  CON- 
STELATION 

MILES 

IN 

Saturn 

886 

73 

29.46  Yrs. 

2*  Yrs. 

Jupiter 

483 

88 

11.86     " 

i   Yr. 

Mars 

142 

4 

686  Days 

5  7  Days 

THE   SUN 


133 


THE  SUN 

THE  possessor  of  a  three-inch  telescope  may  derive 
much  pleasure  and  profit  by  observing  the  sun,  but 
great  care  must  be  used  or  the  sight  will  be  permanently 
impaired.  Many  telescopes  are  equipped  with  shade 
glasses  of  neutral  tints,  which,  when  screwed  to  the  eye- 
piece, admit  of  direct  solar  vision.  If  this  method  is  used, 
the  aperture  of  the  objective  should  be  decreased  by  means 
of  a  diaphram  placed  over  the  objective,  otherwise  the 
heat  is  liable  to  crack  the  solar  eyepiece,  thus  endanger- 
ing the  eyesight. 

A  smoked  glass  may  also  be  used  in  place  of  a  solar 
eyepiece,  and  answers  very  well  if  it  is  well  covered, 
but  it  is  a  dangerous  method  to  employ,  and' rather  than 
take  the  risk,  the  method  of  viewing  the  sun  by  pro- 
jecting its  image  on  a  screen  should  be  adopted.  This, 
in  addition  to  being  perfectly  safe,  permits  a  number  of 
persons  to  view  the  solar  phenomena  at  the  same  time. 
It  is  best  to  fasten  the  screen  to  the  telescope  by  a  light 
framework,  over  which  a  black  cloth  should  be  stretched 
to  keep  out  the  light,  and  render  the  image  more  dis- 
tinct. As  a  further  screen,  the  object  glass  should  be 
allowed  to  project  through  a  piece  of  cardboard. 


136  The  Sun 

It  is  unnecessary  and  dangerous  to  locate  the  sun  by 
the  use  of  the  finder,  as  by  experimenting  a  little  the  sun- 
light can  be  made  to  appear  on  a  paper  held  close  to  the 
eyepiece. 

If  one  can  afford  it  the  most  satisfactory  views  of  the 
sun  are  to  be  had  through  a  solar  prism,  or  a  helioscope, 
which  enables  the  observer  to  control  the  amount  of 
light  passing  through  the  eyepiece,  and  permits  of  a 
direct  view  of  the  solar  phenomena  without  running  any 
danger  of  ruining  the  eyesight. 

The  phenomena  of  especial  interest  to  the  observer 
with  a  small  telescope  are  the  sun  spots.  There  is  sel- 
dom a  time  when  there  are  not  one  or  more  spots  on  the 
sun,  and  the  changes  to  be  noted  in  them,  and  their 
apparent  daily  motion  aoross  the  sun's  disk,  are  well  cal- 
culated to  interest  the  student;  especially  when  he  con- 
siders the  magnitude  of  many  of  the  spots,  as  he  can  well 
do  by  comparing  them  with  the  diameter  of  the  sun,  which 
is  866,000  miles. 

The  mean  rotation  period  of  the  sun  is  twenty-five 
days.  On  the  average,  the  spots  travel  across  the  sun's 
disk  in  a  little  over  fourteen  days. 

The  spots  often  change  perceptibly  from  day  to  day. 
Some  are  obliterated  in  a  few  days,  while  others  appear  to 
remain  intact,  and  are  seen  for  several  successive  periods 
of  revolution.  It  is  good  practice  to  sketch  the  spots  as 
they  are  observed.  In  this  way  the  changes  in  their 
appearance  can  be  easily  noted. 


The  Sun  137 

Excellent  views  of  the  spots  may  be  had  through  the 
solar  eyepieces,  by  inserting  between  the  lenses  of  the 
regular  eyepiece  a  piece  /of  cardboard,  which  has  a  hole 
pierced  through  its  centre  with  a  red-hot  needle.  This 
method  brings  to  light  considerable  detail. 

It  has  been  determined  that  the  magnitude  and  num- 
ber of  the  spots  wax  and  wane  in  a  period  of  about  eleven 
years.  Near  a  minimum  time  the  visible  surface  of  the 
sun  may  be  free  from  spots  for  weeks,  while  at  maximum 
they  can  be  seen  almost  every  day,  some  being  large 
enough  to  be  seen  through  a  smoked  glass  with  the  naked 
eye.  A  maximum  was  reached  about  1904-05. 

As  to  the  nature  of  the  spots,  no  theory  as  yet  pro- 
pounded fully  explains  the  phenomena.  It  has  been 
observed  that  during  maximum  periods  of  sun  spots, 
magnetic  storms  on  the  earth  and  displays  of  the  aurora 
borealis  frequently  occur,  so  that  in  all  probability  there 
is  some  connection  between  them. 

Eclipses  are  of  course  of  the  greatest  interest  to 
observe  of  all  solar  phenomena,  especially  the  total 
eclipses,  which  unfortunately  seldom  occur.  In  regard 
to  them,  the  almanac  will  supply  the  necessary  data  as 
to  time  and  visibility. 

The  so-called  solar  prominences  are  the  most  spectac- 
ular of  all  the  solar  phenomena.  They  are  geyser-like 
fountains  of  hydrogen  and  helium  gas  that  spurt  out 
from  the  sun's  surface,  sometimes  rising  to  a  height  of 
350,000  miles.  They  can  only  be  seen  when  on  the  sun's 


138  The  Sun 

limb,  and  then  only  through  a  spectroscope.  It  is 
possible  to  attach  a  spectroscope  to  a  glass  of  only  three- 
inch  aperture  and  surely  to  one  who  can  afford  such  a 
luxury  the  spectroscope  thus  employed  will  yield  a  mine 
of  enjoyment. 

The  matter  of  solar  observation  is  merely  hinted  at 
here.  There  is  a  wealth  of  material  on  the  subject  at 
the  command  of  the  student.  It  is  only  necessary  to 
call  attention  to  the  danger  of  observing  the  sun  with- 
out interposing  a  semi-opaque  medium  and  to  men- 
tion briefly  the  phenomena  observable  in  a  three-inch 
telescope. 

Astronomers  are  paying  more  attention  to  the  sun  at 
present  than  ever  before.  The  fact  that  it  is  the  nearest 
star  to  the  earth  renders  it  most  worthy  of  our  observa- 
tion and  every  new  fact  relative  to  its  nature  and  the 
character  of  its  phenomena  is  of  prime  importance  to 
the  race. 

Because  of  the  strides  now  being  made  in  solar  photog- 
raphy, there  is  every  reason  to  hope  that  in  the  very 
near  future  the  nature  of  the  sun  spots,  at  least,  will  be 
revealed. 


INDEX  TO  THE  CONSTELLATIONS 

Andromeda  and  Triangulum,  41 

Aquarius,  43 

Aquila,  45 

Aries,  47 

Auriga,  49 

Bootes,  21 

Cancer  and  Canis  Minor,  3 

Canes  Venatici  and  Coma  Berenices,  23 

Canis  Major,  71 

Canis  Minor,  3 

Capricornus,  51 

Cassiopeia,  53 

Cepheus,  55 

Cetus,  57 

Coma  Berenices,  23 

Corona  Borealis,  5 

Corvus,  7 

Crater,  7 

Cygnus,  59 

Delphinus  and  Sagitta,  29 

Draco,  9 

Equiileus,  61 

Eridanus,  73 

Gemmi,  75 

Hercules,  n 

Hydra,  3 


140         Index  to  the  Constellations 

Lacerta,  61 

Leo,  13 

Lepus,  77 

Libra,  25 

Lyra,  15 

Monoceros,  79 

Ophiuchus  and  Serpens,  27 

Orion,  81 

Pegasus  and  Equuleus,  61 

Perseus,  63 

Pisces,  65 

Sagitta,  29 

Sagittarius,  31 

Scorpio,  33 

Serpens,  27 

Taurus,  67 

Triangulum,  41 

Ursa  Major,  35 

Ursa  Minor,  37 

Virgo,  17 


.    INDEX  TO  THE  MOON  ON  THE  DIAGRAMS 

Craters : 

Agrippa,  98 
Albategnius,  98 
Aliacencis,  99 
Apollonius,  93 
Archimedes,  100 
Ariadaeus,  100,  104 
Aristarchus,  90,  104 
Aristillus,  100 
Aristo teles,  98 
Arzachel,  101 
Atlas,  94 
Autolycus,  100 
Beaumont,  97 
Bessel,  98 
Biela,  97 
Birt,  102 
Blanchini,  103 
Bonpland,  103 
Bulliadus,  102,  105 
Burckhardt,  92 
Burg,  97 
Calippus,  98 
Capella,  96 
Capuanus,  103 

141 


142  Index  to  the  Moon  on  the  Diagrams 

Cassini,  100 
Catharina,  96 
Cichus,  1 02 
Clavius,  100 
Cleomedes,  90 
Condorcet,  93 
Copernicus,  102 
Cyrillus,  96 
Dawes,  96 
Delambre,  99 
Endymion,  94 
Eratosthenes,  100 
Eudoxus,  98 
Fabricius,  94 
Fermat,  97 
Firmicus,  93 
Flamsteed,  105 
Fra  Mauro,  105 
Frascatorius,  94 
Furnerius,  92 
Gassendi,  102 
Gauss,  92 
Geminus,  92 
Gemma  Frisius,  99 
Godin,  98 
Grimaldi,  90,  104 
Helicon,  103 
Hercules,  94 
Herodotus,  104 
Herschel,  101 
Hevelius,  102 
Hipparchus,  98 
Hommel,  96 


Index  to  the  Moon  on  the  Diagrams  143 

Hyginus,  100 
Isidore,  97 
Kepler,  102 
Lambert,  103 
Langrenus,  92 
Lassell,  103 
Le  Monnier,  96 
Letronne,  102 
Linne,  100 
Littrow,  96 
Longomontanus,  103 
Macrobius,  97 
Maginus,  103 
Manilius,  98,  104 
Maraldi,  96 
Maurolycus,  98 
Menelaus,  98,  104 
Mercator,  103 
Messala,  91 
Messier,  94 
Metius,  94 
Mutus,  97 
Newton,  102 
Parry,  103 
Petavius,  92 
Picard,  90 
Piccolomini,  98 
Pico,  102 
Pierce,  90 
Pitatus,  103 
Pitiscus,  96 
Plato,  102,  104 
Pliny,  96 


144  Index  to  the  Moon  on  the  Diagrams 

Polybius,  96 
Pons,  96 
Posidonius,  96 
Proclus,  94,  104 
Ptolemy,  102 
Purbach,  101 
Pytheas,  103 
Reinhold,  105 
Rheita,  97 
Roemer,  96 
Santbech,  97 
Scheiner,  103 
Silberschlag,  101 
Stadius,  103 
Steinheil,  97 
Stiborius,  97 
Stofler,  98 
Street,  103 
Sulpicius  Gallus,  98 
Taruntius,  97 
Taylor,  99 
Theaetetus,  98 
Theophilus,  96 
Timocharis,  103 
Tobias  Mayer,  102 
Tralles,  90 
Tycho,  98 
Valcq,  96 
Vendelinus,  92 
Vitruvius,  96 
Werner,  99 
Wilhelm  I,  103 
Zagut,  98 


Index  to  the  Moon  on  the  Diagrams  145 


Mountains : 


Alps,  100 
Altai,  96 
Apennines,  100 
Carpathian,  102 
Caucasus,  98 
Hsemus,  96 
Harbinger,  104 
Leibnitz,  94 
Riphaean,  104 
Taurus,  96 
Mt.  Argaeus,  96 
Mt.  Hadley,  100 


Ssas: 

Mare  Crisium, 

Fecunditatis, 

Frigoris, 

Humorum, 

Imbrium, 

Nectaris, 

Nubium, 

Serenitatis, 

Tranquilitatis 

TT  _    ._ 


Sea  of  Conflicts,  90 
Fecundity,  94 
Cold,  104 
Humors,  102 
Rains,  104 
Nectar,  94 
Clouds,  102 
Serenity,  98  • 
Tranquillity,  97 
Mists,  100 


Vaporum,  Mists,  100 

Oceanus  Procellarum,  Ocean  of  Tempests,  104 


Capes : 

Cape  Agarum,  90 
"      Heraclides,  102 
"      La  Place,  102 


146  Index  to  the  Moon  on  the  Diagrams 

Bays  and  Gulfs : 

Sinus  ^Estuum,  Gulf  of  Heats,  100 
Iridum,  Bay  of  Rainbows,  102 
Roris,  Gulf  of  Dew,  104 

Other  Formations : 

Lacus  Somniorum,  Lake  of  the  Sleepers,  96 
Lunar  Railroad,  or  Straight  Wall,  102 
Palus  Somnii,  Marsh  of  a  Dream,  94 
Palus  Putredinis,  Marsh  of  Corruption,  104 


THE 

UNIVERSITY 

OF 


Books    on    Astronomy 


Hal f=H ours  with  the   Stars 

A  PLAIN  AND  EASY  GUIDE  TO  THE  KNOWLEDGE  OF  THE  CON- 
STELLATIONS, showing,  in  12  maps,  the  position  for  the  United 
States  of  the  Principal  Star  Groups,  night  after  night,  through- 
out the  year,  with  an  introduction  and  separate  explanation  of 
each  map.  True  for  every  year.  Maps  and  text  especially 
prepared  for  American  students.  By  RICHARD  A.  PROCTOR, 
F.  R.  A.  S. 
^°,  boards  .  ......  $2  oo 

This  is  an  entirely  new  edition,  with  new  plates,  prepared  ex- 
pressly for  American  students,  of  a  work  which  in  its  oiiginal 
London  issue  has  attained  exceptional  popularity. 

44  No  teacher  who  has  the  responsibility  of  instructing  a  class 
in  astronomy  can  afford  to  be  without  it.'' 

Chicago  School  Herald. 

Easy  Star    Lessons 

By  RICHARD  A.  PROCTOR,  F    R.  A.  S. 

With  48  Star  Maps  and 35  other  Illustrations       .       8°      $2  30 
"  Nothing  so  well  calculated  to  give   a  rapid   and  thorough 
knowledge  of  the  position  of  the  stars  in  the  firmament  has  ever 
before  been  designed  or  published." —  Weekly    'limes. 

An  Easy  Guide  to  the  Constellations 

By  JAMES  GALL,  author  of  "The  People's  Atlas  of  the  Stars,"  etc. 
New  and  Enlarged  Edition  with  30  Maps,  idmo,     73  cts. 
"  Excellently   arranged   and   copiously   illustrated,    it   should 
prove  a  valuable  handbook  for  all  who  want  to  become  familiar 
with  the  stars." — The  Independent. 

The  Stars 

By  SIMON  NEWCOMB,  Retired  Professor  U.  S.  Navy. 
<?°,     Illustrated.    No.  gin  the  Science  Series.   (By  mail,  $220) 

Net  $2  oo 

"  The  work  is  a  thoroughly  scientific  treatise  on  stars.  The 
name  of  the  author  is  sufficient  guarantee  of  scholarly  and  accu- 
rate work." — Scientific  Anitrican.  % 

Q.  P.  Putnam's  5ons 

New  York  London 


Excellently  arranged,  and  copiously  illustrated,  this 
little  manual — a  real  Jleld=book — should  prove  valuable 
for  all  who  want  to  become  familiar  with  the  stars. 


A  Field  Booh 

of  the 

Stars 

By  William  Tyler  Olcott 

Author  of  "In   Starland  witH   a  THree-IncH 
Telescope,"  etc. 

16°.     With  over  50  Illustrations  and  Charts.    $1.00  net. 

To  facilitate  the  fascinating  recreation  of  star- 
gazing, the  author  has  designed  this  field  book. 
All  matters  of  a  technical  or  theoretical  nature 
have  been  omitted.  Only  what  the  reader  can 
observe  with  the  naked  eye  or  with  an  opera-glass 
have  been  included  in  it.  Simplicity  and  brevity 
have  been  aimed  at,  the  main  idea  being  that  what- 
ever is  bulky  or  verbose  is  a  hindrance  rather  than 
a  help  when  one  is  engaged  in  the  observation  of 
the  heavens. 

G.  P.  PUTNAM'S  SONS 

New  York  London 


RETURN     CIRCULATION  DEPARTMENT 

202  Main  Library 


LOAN  PERIOD  1 
HOME  USE 

2                               3 

4 

5                               6 

ALL  BOOKS  MAY  BE  RECALLED  AFTER  7  DAYS 

1-month  loans  may  be  renewed  by  calling  642-3405 
1-year  loans  may  be  recharged  by  bringing  the  books  to  the  Circulation  Dttt 
Renewals  and  recharges  may  be  made  4  days  prior  to  due  c 

DUE  AS  STAMPED  BELOW 

,  oAM 

1^1  I  *-•* 

|  K  M  «J 

uM,v.  o?  cw 

1  '  " 

iFo  BSHl^ 

UNIVERSITY  OF  CALIFORNIA,  BERKELEY 
FORM  NO.  DD6,  60m,  1/83          BERKELEY,  CA  94720 


YB  55429 


